If someone were to win a contest on 11W where a t-shirt was offered as the prize, how would that person go about claiming the prize?

I have never won anything at any time in my life so I have no idea how this works. I thought one of the Mods would have already shown up on my doorstep Ed McMahon-style to hand-deliver my t-shirt.

(MOD EDIT - the title, for additional pizzazz. Congratulations.)