This is gonna be my first tourney. Do i have to pick my main before a match or can i just pick it on the fly? still not sure how the picking of the first round goes without one person having the advantage in picking second.
Technically, you do blind picks. Most people just pick their main first game, unless they know what character the other person uses before hand. You COULD be a scumbag and wait for the other person to pick first, but that's generally just really poor sportsmanship. So, you generally just pick whoever you want right away first game (preferably your main.)
EDIT: whoops, didn't see that people already answered this, sorry
thanks another thing i wasnt sure about was how counter pick courses worked do both players have to agree on the counter pick?
Well, I'm only speaking for Project M and Melee, but after the first game, you go straight to stage select. Winner of the first match bans 1 stage in Melee, or 2 stages if you're playing Project M. Loser then picks the stage. Finally, you go back to the character select before starting, and the winner picks his character (usually the winner will just stay the same here) and then the loser picks their character. Then you just start with those characters on whatever stage you picked.
There's also something called Dave's Stupid Rule (DSR) that states that if you won on that stage in the set, you can't counter pick to it. Hoped this helped