Doing my first giveaway and...

thanks

Do you have a specific query about it, or just general information?

Thanks for Skyrim?

You create your giveaway, when it end you gift the game to the winner, you click on sent and he clicks on received. If you don't send the game, he will click on not received after a week. That's how the received/not received info appears on your profile.
That's pretty all there is to the rating system.