ERP Studio — Construction Management System

1What the system does

ERP Studio brings a building contractor's back-office work together in one place — from issuing quotations and construction contracts, controlling the budget against the BOQ, ordering materials, logging equipment hours, paying wages and controlling site work, to issuing tax invoices, keeping the books and closing the financial statements. Every module refers to the same project name, so you see the cost and progress of each job straight away, and the whole team works on one data set.

2Permissions and data storage

Where the data is stored

• Stored on your account — when the database is reachable, data is saved to the system and loaded back every time you open the page. Open it from another computer or a phone and you see the same data set
• Updates instantly when someone else edits — if a colleague is editing at the same time, the figures on your screen refresh by themselves
• Keep working even if the connection drops — the system keeps a copy in the browser and sends it up once you are back online
• The whole team works on one data set — the procurement, equipment, workforce, finance and site control modules and the construction contract text are stored record by record in a shared table, so two people can edit different records at the same time without overwriting each other · the first time after the administrator switches on the shared table, a blue bar Move to the shared table appears so you can move the data previously kept in your account into it (the original data is kept as a backup)
• Every edit is logged — who changed what, from which old value to which new value, can be seen in the Approvals & history menu (section 11); the log cannot be edited or deleted
• Nothing left on the device after logging out — the system clears the browser cache copy every time, so a shared computer is safe to use

Confirmation pop-up before deleting or overwriting

Every button that makes data disappear or be replaced always shows an “Are you sure you want to…” pop-up first. The pop-up states the item name, number and how many records will actually be lost; read it before pressing — there is no undo button after you confirm

Besides every delete button (projects, documents, contracts, purchase orders, escalation K, workforce, equipment, site records, etc.), the pop-up also appears first in these cases:

• Cancelling a tax invoice / credit-debit note from the status field — once cancelled it cannot be reverted; the safe-side button reads Keep it
• Reopening an accounting period — the trial balance stored at period close will be cleared
• Deleting a line in a journal voucher or an escalation (K) record · deleting a stage-of-completion adjustment · deleting a custom account
• Closing a document or contract form that has been filled in but not yet saved (an empty form closes straight away)
• Buttons in the contract form that overwrite what you typed — pull the project's work phases · split the price evenly · use our company details

3Tour of all 12 menus

The left-hand menu has 3 groups — Main menu · Head office · Site support · The orange number on a menu item is the count of outstanding items waiting for you

At the top of every page there is a Search documents, projects… box and a Create document button you can press from anywhere · the bottom-left corner has links to this manual, the privacy policy, the terms of service and your user profile · switch between Thai and English with the TH/EN button at the top

4Settings before going live

This takes about 15 minutes, but it makes every document, tax invoice and accounting figure issued from then on correct from the very first one

1. Fill in the user profile and company information

   Click the profile picture in the bottom-left corner → Edit user information · fill in full name, position, department, email, phone, company name, company address, 13-digit tax ID and office/branch no. — this data appears as the seller on tax invoices, the payer on 50 Tawi certificates and the data controller in the PDPA record of processing

2. Upload the company logo

   Click the picture to attach a file · a file of 1.5 MB or less is recommended (large files make saving slow or fail, so shrink the image first) · this logo appears at the top of every PDF document

3. Set the opening cash and the books start date

   Menu Finance, accounting & tax → tab Cash flow: enter the opening cash · menu Ledger & statements → tab Chart & close: set the books start date (normally the first day of the accounting year) — the system uses these two values to calculate the brought-forward balances

4. Check the social security rate

   At the bottom of the timesheet tab in the Workforce & wages menu — the default is 5% with a wage ceiling of 17,500 THB/month; change it when the Social Security Office announces a new rate

5. (Administrator) Check the approval amount rules

   Menu Approvals & history → tab Approval rules — the amounts that require management as step 2, by document type; set them to match your company's approval authority

6. Check that documents come out correctly

   Create one test quotation and press Preview / download PDF to check that the company name, address, tax ID and logo all appear

5Projects and work phases

Create a project

In the Projects menu, press Add project and fill in

• Project name and Location — this name is used as the reference in every module, so keep it short and easy to remember
• Project code — set automatically by the system; you can edit it in the Code field on the project card (see Project code below)
• Status — Started · Under construction · Near handover · Completed · On hold
• Budget · Actual cost · Disbursed · Progress
• Colour of the project — used to tell the bars apart on the overall schedule

Drag the handle icon at the top of a card to reorder projects so the jobs being pushed hardest are on top

Project code

A project code must be unique across the whole system — including projects of other accounts you cannot see — so the system assigns codes in two ways depending on the account type

This applies when you press Add project, duplicate a project or add the sample project set · the running number counts only codes in the PRJ-### format; other codes you set yourself, such as CP-2569-014, do not make the number jump

Overall schedule (Gantt)

Each project has its own task bars. Press + Task to add a work phase, then set the start and end dates — the system works out the number of months from the date range, and the Gantt bar moves with it immediately

Contract work phases

Press Add work phase to break the contract value down into phases; each phase has

The work phases entered here appear on the Tax & billing page so you can see which phases have not been billed yet

6Documents and construction contracts

6 document types

Creating a document step by step

1. Press Create document

   The system assigns the document number automatically; you do not need to enter it

2. Choose the document type and project

   Link it to the right project, because the amount is counted into that project's cost or income

3. Enter the partner/client and the dates

   Enter the partner name, document date and Payment due / price validity — this due date drives the “overdue documents” alert on the dashboard

4. Choose the price mode

   Price excl. tax or Price incl. tax — choose whichever was agreed with the client; the system works out the VAT the right way

5. Add items

   Press + Add item and fill in Description · Qty · Unit · Unit price · the system calculates the amount automatically

6. Check the totals at the foot of the document

   Go through Subtotal → Discount → Price after discount → VAT 7% → Total amount → Withholding tax → Net payable

7. Enter notes / terms

   For example, “Price valid 30 days · 30% deposit before work starts · this price excludes work beyond that specified”

8. Save

   Save draft keeps it for further editing · Save & submit for approval sends it to the approval queue

Construction contract (latest 2569 standard form)

Choose the type Contracts and press Create document. The system opens a full-screen contract form divided into 10 steps following the government standard form of construction contract (clauses 1–23 and practice notes (1)–(24)). Fill it in step by step, or jump between steps from the left-hand bar

1. Choose the price mode and your company's role

   Lump sum paid in installments · Unit price paid monthly on the actual quantities of work — the system inserts the text of clause 4 version (A) or (B) for you · choose whether our company is the contractor or the employer, then press Use company details in the parties step to pull the name, address and signatory from the profile

2. Enter the contract price and payment installments

   Enter the contract price including VAT and the system separates out the VAT · for the installments, press Replace instalments (pulls the project's work phases from the BOQ & cost page) or Split evenly; the installments must add up exactly to the contract price

3. Switch optional clauses on or off

   Advance payment · Retention · Use of Thai vessels · Workmanship standards · Additional terms — switch a clause off and the following clause numbers move up by themselves, and cross-references in the text (e.g. “per clause 20”) update to match

4. Look at the “Contract check” panel on the right

   It checks against the practice notes at the end of the standard form, e.g. a warranty of at least 2 years · a subcontracting penalty of at least 10% · a daily penalty of 0.01–0.10% · a security of 5% · a 13-digit national ID number — click an item to go to the step that needs fixing · You can submit for approval once no red items remain, while Save draft is available at any time

5. Preview, print or download Word

   Preview contract shows the whole contract in Thai numerals (can be switched off in the first step); fields not yet filled in appear as dotted lines for handwriting · Print / save as PDF gives A4 with page numbers · Download Word gives a .doc file to keep editing during negotiation

Document status cycle

Draft → Awaiting approval → Approved → Paid

A document past its due date but not yet closed gets an Overdue label and is counted in the “Documents pending” card on the dashboard

Print and send to the client

Press Preview / download PDF to see a preview before printing, showing the company header, the item table, the amounts, the amount in words and the signature blocks for both the Proposer / authorized signatory and the Approver / client · then press Print / save as PDF

7BOQ and cost control

The BOQ & cost menu is the tool that tells you where your profit is leaking

1. Choose a project

   The BOQ is kept per project, so choose the project to view first

2. Add work categories

   Press Add work category and name it, e.g. Piling & foundation work · RC structural work · Architectural work · Electrical & communication systems · Sanitary & fire-protection systems · Labor & site management · Contingency

3. Enter the budget per category

   The total of all categories should equal the contract value less the planned profit

4. Track the actual cost

   The system compares the budget with the actual cost and shows the Variance and a Budget usage bar as a percentage

8Finance, accounting and tax

The Finance, accounting & tax menu handles money in and out and the tax documents of every project · the journal, trial balance and financial statements are in the Ledger & statements menu (section 9), which posts itself from the documents in this menu

6 tabs — Payables (AP) · Receivables (AR) · Tax invoices · Escalation (K) · Cash flow · Tax & billing · the orange button in the top-right corner changes with the open tab (New payable · New billing · New credit note · New K record)

Payables (AP) — money we have to pay

Press New payable, or use the Book payable from… button to pull from purchase orders that are approved but have no payable booked yet — the system splits out the tax base automatically

Fill in Doc no./ref · Supplier · Project · Tax base · WHT % · Payment due · Paid · Status (Draft · Awaiting payment · Partially paid · Paid · Cancelled)

The reference number determines the expense account — a purchase order reference (PO-…) posts to materials · a subcontract reference (SC-…) posts to subcontractor costs · anything else posts to other construction costs — you can change the account in the journal (section 9), e.g. choose account 1210 for an equipment purchase

Receivables (AR) — money the client has to pay us

Press New billing and fill in Doc no./instalment · Project owner · Value · Retention % · Collection due · Received · Status (Draft · Billed · Partially collected · Collected · Cancelled) · an increase billing from escalation (K) shows as “K increase” instead of an installment number

Cash flow

• Opening cash — the brought-forward balance used as the calculation base; entered once by hand
• Cash on hand = opening + cash received to date − cash paid to date
• Expected in / Expected out — forecast from the due dates of outstanding billings and payables

Tax & billing

Tax invoices · credit notes · debit notes

The Tax invoices tab is the register of full-form output tax invoices under Section 86/4 · construction work is a service, so the tax invoice is issued when payment is received (Section 78/1), not at billing

1. Issue from a billing that has been paid

   Enter the “Received” amount in the Receivables tab, then press the → Issue tax invoice from AR-… button; the system creates a draft. A partial receipt calculates the tax base in proportion to the money actually received · the buyer's name, address, tax ID and branch are pulled from the previous tax invoice of the same buyer

2. Check the buyer's details

   It must have the name, address, 13-digit tax ID and head office/branch · if anything is missing an orange label says so, and the status cannot be changed to “Issued”

3. Issue and print

   Change the status to Issued and press 🖨 — you get the original and a copy, showing withholding tax and retention as deductions, so the net received equals the money actually received

Output VAT in the tax tab is calculated from tax invoices issued in the month + debit notes − credit notes; press 🖨 Output VAT report to print the monthly output tax report under Section 87 to support the PP.30 filing · e-Tax Invoice by Email — enter the buyer's email, then press ✉ Email (e-Tax) on the preview page; the system opens your email program with a copy to the ETDA time-stamping system (attach the PDF yourself). This works once you have registered for the service with the Revenue Department

Withholding tax certificate (50 Tawi)

The Withholding tax certificates (50 Tawi) card in the tax tab shows payables with tax withheld that were paid in the selected month (counted by actual payment date) · enter the 13-digit tax ID and the address of the payee, check the filing form (PND.53 for juristic persons / PND.3 for individuals — the system guesses from the name first), then press Print 50 Tawi to get the certificate on the Revenue Department form in two copies (copy 1 attached to the return · copy 2 kept as evidence) · a payer who does not issue a certificate is liable to a penalty under Section 35 of the Revenue Code · remit the tax by the 7th of the following month (the 15th when filing online)

Below is the Progress billing by instalment table, which pulls the work phases from every project and matches them against the billings already issued — any phase not yet billed can be turned into a receivable in one click

Escalation (K) — price-adjustable contracts

The Escalation (K) tab calculates the increase/decrease in construction payments under the Cabinet resolution (letter NR 0203/W 109 dated 24 August 2532), with all 35 formulas in 5 groups (building · earthwork · highway · irrigation · utilities). It is used for public-sector contracts and for private contracts that agree to use the same formulas

1. Enter the monthly price indices

   Press + Add month and enter the indices published by the Ministry of Commerce (price.moc.go.th) — enter them once and every contract uses them · the table shows only the indices used by the formulas in your contracts; press Show all 13 indices to see them all · orange cells are indices a contract needs but that are still blank

2. Open a K record for the contract

   Press + New K record, choose the project, and enter the contract number, the employer, the Bid opening month (o) and the contract end month

3. Enter the installments

   One line per work type per installment — choose the formula, the delivery month (t) and the work value Po of that type in that installment · an installment containing both building work and piling must be split into two lines, because they use different formulas

4. Check the results and print

   Hover over a K value to see the calculation index by index · press 🖨 to print the worksheet to attach to the payment claim letter · press → Bill increase and the system creates a draft receivable billing for just the amount not yet billed (with VAT taken out, because the contract work value already includes VAT)

9General ledger and financial statements

The Ledger & statements menu is a double-entry accounting system per TFRS for NPAEs (Thai Financial Reporting Standard for Non-Publicly Accountable Entities, revised 2565) — most journal entries post themselves from documents the team already keeps, with no re-entry

1. Set the books start date

   Tab Chart & close — normally the first day of the accounting year · the opening balances are calculated automatically from the opening cash, documents before that date and the equipment, with the difference going to retained earnings · other opening balances (registered capital, loans) are recorded with a journal voucher

2. Record items that have no document in the system

   Press + New journal voucher, e.g. interest, office expenses, remitting tax/social security, corporate income tax · it can be posted once debits equal credits; once posted it cannot be edited — if wrong, press ↺ Reverse

3. Adjust revenue by stage of completion

   Tab Stage of completion: enter the total contract revenue, the estimated total cost and the measurement method (survey of work performed, or cost incurred ÷ total cost), then save at period end (chapter 20)

4. Check and print the statements

   Trial balance · statement of financial position · income statement · statement of changes in equity, in the chapter 4 format · export the journal as CSV for your bookkeeper

5. Close the period

   Once closed, vouchers in that period cannot be edited and the system stores every account balance; if someone edits a source document afterwards, a warning appears with the accounts that changed · only an administrator or the account owner can reopen a period, and the system asks for confirmation first, because the balances stored at close will be cleared — when you finish the corrections, close the period again

10Personal data (PDPA)

The ERP holds personal data of outside parties — workers, contract parties (including national ID numbers and bank accounts), buyers, vendors and subcontractors · your business is the data controller under the Personal Data Protection Act B.E. 2562, while Chang Pile is the processor on your behalf (Terms of Service, clause 7/1) · the Personal data menu helps you carry out the controller's duties

11Approvals and change log

The Approvals & history menu under Head office is the internal control for document work — the number on the menu is the count of items waiting for your approval · if the menu says it is not switched on yet, tell your administrator

Covers quotations, contracts, purchase orders, invoices, progress-payment claims (not RFIs), plus purchase requests, purchase orders and variations in the modules · Default thresholds: quotation 2,000,000 · contract/invoice/progress claim 1,000,000 · purchase order 200,000 · purchase request/variation 100,000 THB

12Procurement and inventory

This module has 4 tabs that work one after another like a conveyor belt

Purchase requests (PR) → Purchase orders (PO) → Site receipts & issues → Site material stock

1 · Purchase requests (PR)

Press New purchase request and fill in PR no. · Project/site · Material item · Quantity and unit · Requested by · Required by · Estimated value

The status runs from Draft → Awaiting approval → Approved → PO issued (or Cancelled) · changing it to “Approved” goes through the approval workflow; the requester cannot approve their own request (section 11)

2 · Purchase orders (PO)

For a purchase request that is Approved, press the Issue PO from… button to carry the items straight into a PO, then fill in the vendor name and the Delivery due date

The Goods receipt field has three values — Not received · Partially received · Fully received · once the delivery due date has passed, chase the vendor

3 · Site receipts & issues

Press Log receipt / issue every time goods arrive on site or are issued out, and fill in Date · Type (Received/Issued) · Material · Quantity · PO or issue slip no. · Receiver/requester

4 · Site material stock

Summary figures at the top

• PRs awaiting approval · Open purchase orders · Materials below reorder point · Stock value on hand

13Equipment management

4 tabs — Equipment register · Usage log · Maintenance plan · Depreciation

Equipment register

Press Add equipment and fill in Code · Equipment name · Type (Excavator · Pile driver / rig · Truck · Mobile crane · Site tools · Generator) · Current site · Status (In service · Idle · Under maintenance · Held for disposal)

Usage log

Log every day the machine works, filling in Date · Equipment · Hours · Fuel (litres) · Operator · Work done

Maintenance plan

Press Add maintenance plan and fill in the maintenance task (e.g. engine oil change) · Interval (hrs) · Last at (hrs) · Last service date

Depreciation

Fill in Purchase cost · Purchase date · Useful life (years) · Salvage value, and the system does the calculation

14Workforce and wages

3 tabs — Workers & subcontractors · Timesheets & wages · Subcontracts

Worker register

Press Add worker and fill in Full name · Position (Foreman · Steel fixer · Mason · Formwork carpenter · Electrician · Plumber · Equipment operator · General labourer) · Affiliation · Site · Wage/day · OT/hr · Status (Active · On leave · Left)

Timesheets & wages

Press Log timesheet and choose Period date · Worker · Days · OT hrs

Social security and statutory overtime

• Social security, Section 33 — tick the SSO box in the worker register only for people the company employs directly (subcontractor crews have contributions deducted by their subcontractor). The system deducts 5% of wages, accumulating per person per month so the ceiling is not exceeded · the rate and wage ceiling (default 17,500 THB/month) can be changed at the bottom of the timesheet tab when the Social Security Office announces a new rate · the employer contributes the same amount and remits it with form SPS 1-10 by the 15th of the following month
• Overtime — Labour Protection Act Section 61 requires OT on working days of at least 1.5 times the hourly wage (daily wage ÷ 8) · an OT/hr value below the minimum turns red, with a warning bar stating each person's minimum rate

Subcontracts

Press Add subcontract and fill in Contract no. · Subcontractor name · Scope of subcontracted work · Contract value · Claimed · Retention (%) · Status (Draft contract · In progress · Nearing completion · Completed · Suspended)

15Site control

Brings together in one menu the work that site supervisors and project engineers do every day; the number on the menu is the count of open NCRs

16Reading the dashboard

17Daily, weekly and monthly routines

18Frequently asked questions

19Glossary of system terms