How to pay a GC? How to figure out scope of work?

[Rigo V.]

how you do pay your GC? If the GC requires a deposit and the HML only pays after work is completed (completely makes sense) does the deposit come out of pocket?

Also, I read a few times that your quotes from GC’s need to be have a specific scope of work and in writing. Do I need to have the type of materials I want used? What if I don’t know that exactly.