First things first, join this steam group. I occasionally get notifications that there are games going on and they need slots to fill.
Whippersnapper is a good guy to talk to for getting into the PVP scene. Its a little old, but you may way to try responding to this topic.
If possible, you may want to try getting some games in on your own before doing the main PVP games. Not all the players are as noob friendly as Whippersnapper. Sometimes I would just start 1v1 games and see if anyone else who was waiting for a game wanted to play a fast one.
Multiplayer PVP games do play quite differently than against the AI. You might want to read up on some things. If you need some general game tips as well, start with my guide. The one below that is one specific for Multiplayer PVP that assumes you already know some things about the game.
http://steamcommunity.com/sharedfiles/filedetails/?id=116451419
http://steamcommunity.com/sharedfiles/filedetails/?id=161168470#
