if u are the choose one
u will receive the email (just check your email acc)
and your acc will have right to join beta
around 10-20days only base on you are lucky or not
of course,u can also join the beta forum to discuss beta (same place in EQ forum)
in that place u can get many beta info (spell/ loot/ nm /raid info )
Yeah, I was in beta for 2 expansions when was with Triton. GM raided with the guild and walked thru the whole raid to see if any bugs before the release.