A) This is a well-known issue... no need to make yet another new thread about it. Post in one of the already-created threads.

B) You find the code where all other codes are distributed since the dawn of the internet: Your Email... If it's not in your Inbox, check your spam folder just in case. If you don't receive anything at all, contact SE.

I haven't done anything with my code, yet, but from what I gather--and someone correct me on this--you can enter your first code now, but the second code you receive won't be able to be activated until SE says you can, around the start of "Early Access." So, if you end up attempting to enter your second code and it says, "NO, GO AWAY," it's not broken or anything. Don't worry. Still got 3 months, anyway, so don't stress out about it. =D