In order to join a ladder, you will need to go to the 'Ladder Management' link in the 'Members' section. From there, you can join any ladder you want to. You can then go to the actual ladder view and make challenges to anyone, or even groups of members. If you challenge a group of members, then you will need to play them all at the same time in order to post the scores.
If you are still having trouble with the bb, let me know.
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Grand Moff Kadann, Dark Lord
Head of the Vast Empire High Council
Grand Master of the Dark Jedi Order
HHC/GM/GM Kadann/HC-1/DC-1/mSSD Atrus {EE}{MoH}{TT}{SY4}