Thanks for your interest. To join «BuA», in general you need a referral from a current clan member, but in any circumstance you would need to go to
http://bua.beyondunreal.com/, click on the "Join" link, read the rules and send AX your application information. Afterwards, if your application is favorably viewed, you would be tested by at least three Alpha Squad members, to determine your overall skill level. If you were to pass the try-out, you would then be accepted into «BuA» as a probationary member.
All this may seem like a lot, but we've discovered over the past two years that we must take these precautions to weed out people who aren't serious about being in the clan. We want dedicated members that will make positive contributions to the clan, and not people who just want to be able to say they are in one.