If you do not have an Excel to import, you build the budget directly in Hemma. The page starts you off with a canonical template covering the standard Belgian build categories — you keep what fits and rename, remove, or add the rest.
Open Budget from the main navigation. If your project does not have a budget yet, you land on an empty state with two options: Import from Excel and Build from scratch. This article covers the second.
You do not need final numbers. A rough estimate per category is enough to get going — you can refine later, and any invoice or quote that lands afterwards will still find its budget line.
Hemma seeds the tree with the canonical budget template: fourteen roots that match how Belgian construction projects are normally costed — earthworks and sewage, rough construction, roof, exterior joinery, technical systems, and so on. Each root has a handful of common children underneath.
Treat the template as a starting frame, not a constraint. The work is to make it match your build:

On the budget tree, every row has a small row menu and an inline editor. The pieces you can set on a budget line:
Add a child line by opening the row menu on the parent and choosing Add child. Add a new root the same way from the toolbar. The tree can go as deep as you need, but two or three levels is usually plenty — Roof → Tiles, not Roof → Sloped → North → Tiles.
Estimated is the number someone gave you. Budgeted is the number you have decided to spend. They are deliberately separate so you can see the gap.
If you only have one number, put it in Budgeted and leave Estimated blank. The budget page is colour-coded against budgeted — that is the column that drives the on-track / at-risk / over signal in reading your budget status.
Do I have to use the canonical template? No. You can delete every seeded line and start from a blank tree. Most people keep the structure and prune from there because rebuilding the categories from scratch is slower than removing the ones you do not need.
Can I import later? Yes. If your architect sends you an Excel halfway through, you can still run the import — see importing a budget from Excel or CSV. The mapping wizard will line your imported items up against what you already built.
What if I add a line after invoices have arrived? Fine. The invoices stay where they are. Open the invoice and link a line item to your new budget line — see linking an invoice or quote to a budget line.
Can I rearrange the tree later? Yes. Drag a row to a new parent in the tree, or use the row menu to move it. Existing links to invoices and quotes follow the line.