I'm not sure what exactly you're confused by so I'll take it from the beggining. You said setup combos so I assume you mean cancelling strings into drone specials.
If you're just starting to learn her then the forst thing to do is practice drone cancels in practice. Practice with b332 and b14 on hit. It's not like a special move where you can input all the moves in one fluid motion and it will come out. You almost want to input the drone attack one it looks like sonya has recovered from her string.
Once you've got the hang of that then try practicing it on a blocking opponent because the timing on hit is different to the timing on block.
Then once you've mastered that set ai to block random combo and try hit confirming on block and hit the correct timing for the special move.
It can take a bit of getting used to but I'm sure youll get it. If this hasn't asnwered your question then just ask again