I'm gearing up for a POP (Pokemon Organized Play) League. I know it is actually a "league." But I don't know how they work. Are they like a tournament or something?
you get points based on the outcome. the person with most points wins, that's why it's call a league.
Since nex gave you a suitable answer I can now post something that's way off topic but is relevant to the discussion: When the event you'll be attending to Begins, the event coordinators will reveal to you that the evil power is the United States Government & they will teach you how to destroy it as that is Primary Main Objective.