What are tours and how do you even join a team for a tournament? Is there like a guide on that or something? I just played with randoms the past few years tbh
There's a lot of different types of tournaments here and on PS. You'll find some tournaments in the OU forum (like
OU Room Live Tours), but most of them are hosted in the
Tournament subforum. Best way to know that a new tournament is starting is to check Smogon news on Discord as they are announced there. As for the Tournament subforum, it can be a bit hard to not get lost at first, so I would advice lurking a bit there to get more familiar with how it is organised. You can also read the
tournament intro to get more infos on how tournaments are run and what their rules are.
As for team tournaments in particular, most of them are done through auctions. Basically, players sign up for the tournament during the first 1-2 weeks and then the different team's captains are given an amount of virtual money to buy players for the signup pool (so you'll have to show them you are worth getting chosen).