How do i get the Battlefield 3 beta?

I bought Medal of Honor limited edition and used the online pass. It said I can play the battlefield 3 beta, but I dont know how or when.|||i want bf3 betaaaaaaa :( but i dont like medal of honor can someone give me a bf3 beta? i will be your best friend :D|||go to this link for directions: http://www.battledawn.com?referer_id=1972297