I have a problem with projects with a construction company.

This company works as follows:

They sell an industrial warehouse, and once the client accepts it, they generate a project. When executing it, they have to take small materials or auxiliary materials, which are not itemized in the budget and cannot be billed to the client, but do affect the profitability of that project. If they take small materials worth €1500, that value would need to be deducted from the project's balance.

I am writing this to see if anyone knows of any explanatory videos regarding projects that delve into this issue, or if someone can help me and indicate how to do it.

Thank you very much