It's not open to everyone. It is open to STH and they are notified days in advance of the game privately by the Devils. Usually the team will tell the winners that they won one of them or that they won a "prize" and to be at the game that night.
While teams claim it is randomly chosen out of the STH pool, most teams seem to give a preference to those who spent the most amount of $ on tickets and longest tenure in that order.
Last year, which was the first year, the players wore a brand new set for warmups. Then for the actual game against Toronto they switched to their regular set 3's that they have been wearing for a few weeks. After the game they went back to the locker room, quickly switched back to their warmup sets and those were the ones that they gave away to the winners. Therefore the guy who won the Elias last year is probably thinking he got his last game and last goal jersey, but he really doesn't.
This year Meigray said the players wore a brand new set for the entire game and they gave those away to the jerseys off their backs winners. The warmup set with the Patty patches, no one knows what happened to those yet.