The best study guide you can get is to go to your local DMV and get a copy of the state issued guide from them. If it lists something you dont understand youtube and google help a lot.
Didn’t click link but that’s just a pretrip list? Class B? All you need to know is the names of each item that’s part of the pretrip. Learn the names of each part. Focus on that and the rest is easy.
This may or may not be reasonable, but if I a wanted a Class B, I think I might call the local Uhauls and truck rental places. Tell them your intent and if an arrangement can be made to have you perform a pretrip on them everyday. Maybe trade it for washing the trucks, cleaning the trucks, $20 a day rental or something.