I would assume that it would alternate as it has in the past, to allow for one team to set up while the other leaves the field. I haven’t gotten through all the rules yet, though, so I may be wrong.
I’ve read the rules and found no mention of where your robot starts. I seem to remember that it’s changed in past years, could be wrong, so I have no idea.
Historically in qualification rounds, its been determined randomly, as are your alliance partner and your opponents, and I assume this year will be no different. You will be told whether you are on the right or the left. In elimination rounds, historically the alliance captain has been able to choose whether you or your partner is on the left or right, and I again believe this year no different.