Welcome, glad to see someone with strong motivation to become a comp player.
For any questions regarding competitive play, I'm sure @OrangeManiac would be more than happy to help.
He's been in the Tier Council and has written a bunch of guides on competitve pokemon for a few years now.
As for teams, there are a few competitive English speaking teams such as AURA, VVVV and LYLE active at the moment.
I suggest VVVV, as that's the team I'm in right now and that makes me totally not biased /s
Disclaimer: Pokemon Comp play is quite often rng reliant, more than Hearthstone, almost comparable to poker, so prepare for unlucky losses.