1. Visit Gog.com and login to your existing account or create a new one if needed.
2. Scroll down and click on the “Redeem Code” tab or just click here.
3. Enter your game code in the designated area and click on the “CONTINUE” button.
4. As stated above, you will be able to see what you are getting as a game and decide whether you want to buy it back or cancel it. If you decide that you do not want to redeem the code, click the "Cancel" button.