According to the original post this registers on steam. You should get a code that you enter in the Steam client, and you will be able to download the game when it becomes available (or usually just before, so you can have it downloaded and ready to fire up on release date.)
I dont see where can i enter coupon code
If you look at the cart page, there’s a message that says where you enter coupon codes: “Coupons can be entered on the Review & Submit Order page.”
Never used Gamfly before, how does it work? Do you have to use the GameFly Client?
According to the original post this registers on steam. You should get a code that you enter in the Steam client, and you will be able to download the game when it becomes available (or usually just before, so you can have it downloaded and ready to fire up on release date.)