what sections do i need to study for RV hauling for my CDL

A combination over 26k GCWR which is operated for any commercial purpose requires a CDL. If the unit in tow is under 10,000 GVWR, a Class B will suffice. If the vehicle in tow exceeds 10,000 GVWR, a Class A is required (again, in both cases, if the Gross Combined Weight Rating exceeds 26,000 lbs.). The exemption for RVs from requiring a CDL specifically states that it applies when the vehicle is operated for personal use - not for commercial purposes.
As for air brakes, you need an air brake equipped vehicle to road test in, or you'll get the "no air brakes" restriction. General knowledge and combination vehicles should be all you need.