You need Pilot (usually comes stock with drone, can be upgraded per Rigger 5 book)
With just pilot, it rolls pilot level as default for everything (so, yeah, pretty crappy)
Autosofts give it the skill side, so now you roll pilot + autosoft (manuevering, targeting, stealth, evasion... whatever you have loaded) and are model specific
Core Book says you can run pilot/2 number of autosofts at once (you can have more slotted, but takes an action for drone to swap)
Rigger book says they can only run an autosoft equal or lower level then pilot rating
Now this changes a bit with RCC - they can now run as many as you allocated from data sharing (but cannot combo with internal ones on drones)
Running thru RCC, same model drone can "share" a single version of the autosoft (I.E. 4 Steel Lynx can all share a single copy of an autosoft, so say you had one manuevering autosoft for steel lynx, then all can use that 1 copy and it only takes up 1 of the shared slots...)
RCC also lets you use higher level autosoft then pilot rating (so pilot 3 can now use Targeting autosoft level 6)
That's pretty much the basics for autosofts and pilot rating. Now have fun figuring out what to roll for AR/VR and jumped in

opinions will vary... good luck chummer!