How to join a tournament-First of all, you have to be in a clan in order to join a tournament (recruitment forums here).
-Secondly, clan leader needs to assign you as commander.
-Once a team commander you can sign your team up for a tournament, see images below.
-When these three things are settled, you are ready, so simply click Join and have some fun!
Navigate to Social tab and from there choose the Clan tab. Here you can see that you are leader of your team (your name is written in green) and that you have members (in this case JSarge and Ufinicie) in your team.
From the Tournaments tab at the left side of the pane you can see which tournaments are available. Pick the one you are joining, and click "Join" from right pane. Now you are ready for the tournament! Be sure that all of your team members are online when the tournament is about to start!