I've also heard there is s a driver's manual. Where can I get it?
You can get the New York State Commercial Driver 's Manual (CDL-10) online or from a DMV office or call center. Study the sections of the manual that apply to the type of CDL you need. The sections of the manual that you need to study are explained in the manual.
And how I can find out which kind of proofs I can bring to the DMV office?
The DMV Document Guide lists all acceptable legal presence and New York State residence proof documents. You must provide us the original documents (not photocopies).