Good questions and for sure the link Dee provided is a good one!
I had the same type questions when I started. As a newcomer not that long ago my experience was that my sponsor (and other friends I made in AA) helped get me thru the period where I was very restless and irritable - just needed to hang in there.
At that point I could make some sense out of working the steps with my sponsor and gain some traction in the program of AA which is different that then fellowship/meetings.
Sponsors are mentors/guides - they will not nor is it their task to keep others sober. But, their knowledge of what it was like - how they worked that program and what it is like now is invaluable.
Glad you're here, keeping staying sober and keep coming back!