What does that mean exactly? The current plan calls for focused testing windows that occur over weekends -- much like what we've seen with Aion recently. As of right now, CBT-1A will begin on Friday, July 24th and will continue until Monday, July 27th. Each of the successive testing windows will be known as CBT-1B, CBT-1C and on down the alphabet until -- we're assuming -- phase two is reached. It's a method that's worked for both Guild Wars and Aion, so we're not too surprised to see it happening with another game.
Invites will be sent out in groups and you can check out the game's answer center for additional details. It's a little confusing, but the important thing to glean from all this is that beta testing is about to begin. Good luck on getting those keys!