I want to play!
I still don't know how to play...
someone teach me how to do this, I wanna join but I dont remember anything about pokemon
Basically, go to the Pokemon Showdown website. Go to teambuilder on the left side and click it. Click new team, format OU, and then the pokemon. There's lists of pokemon builds on Smogon. You can go with Smogon's suggested builds, make your favorites, or whatever and then change it after you battle some people and develop strategy.
If you clear your cookies, it clears your team though, so if you want to use the same team at some point in a few months, you should save it as a list.