The link to tournament section should appear at the top of the site/forums.
Create your clans here. be sure to invite your clan members to join the team.
It is mandatory to create a clan here for any kind of clan activity in BG.
when there's a new tournament/league/ladder, you can join it from here.
you can also discuss/comment on them.
PLEASE read the rules first. (link).
For any questions/comments, head over to the feedback thread here.