If you submit a multiple person run, you have "Player 2" and "Player 3" spaces (and so on with the numbers) to enter their speedrun.com account. For their video, put it in the run description

To submit a run with multiple SRC accounts you type their name exactly how it's written, in each player insert. So for example Player 1: lozplyr89 Player 2: LaurieDeBeaver

If it's not written EXACTLY as intended, it won't work

Yes, it will look like pretty much all runs on the boards