The left actuator is the drivers side. Good news, you don't have to pull the dash to do this one. Lay on the floor, look up, and you'll see it. I did mine in about 30 minutes a couple years ago.
Do yourself a favor and just order a new one from Gene. Indexing just moves the old worn teeth to the other side. Eventually, maybe the day after you do it, you'll have to replace the damn thing. Might as well do once and be done.
Need any help, gimme a call (301)991-0800