Hello question about recieving games ?

When a giveaway ends, the gifter has a week to send the activation key to the winner through the email associated with your account.

You will recieve a message here in the site, it's pretty hard to miss it. :P

It's sent through Steam or email, you'll be notified if you won a gift on the site

refer to the FAQ in the forums

Ideally, the creator of the giveaway will send you an e-mail with the gift. You will also see a green bar on the website when you win.
http://imageshack.us/photo/my-images/20/unledaxr.jpg/

Credit: JooJooFace - You can also click this URL to read other people's responses to the same question.