Ok, we'll do this nice and easy. We need to get some things sorted out.
First off, a big thank you for doing this giveaway. It's nice to spread some joy every once in a while. It's a time honored tradition here.
Most of the time, we put our fellow GOGers through a challenge so they "earn" their games. It can be a complex chore, simple process of elimination or just a random pick of the winner.
The method of gifting is usually as such: the winner picks a game(s), and the gifter then buys it, gifts the codes to himself, and copy/pastes the code to the winner through our Personal Messages (the PM sign if you hover your mouse over an avatar of a fellow user).
That's the usual way, but there really aren't any rules about it. It can be wild wild west for all we care. the point is that it's interesting and fun. (especially for those who get the gifts ;)