1. Get an Xbox Live subscription (at least a silver) and at least 800 Microsoft points.
2. Make sure your Xbox is connected to the internet.
3. Go to the Marketplace and then the Video Store section in the Xbox dashboard.
4. Select "Redeem Code" and enter in the codes on the back of the two cards (in step one).
5. Start up Fable II, press start, select "Downloadable Content".
6. Select the Premium version of Knothole Island
- The free version only allows you to play co-op with someone that has the premium version.
- Stay on the download page until it is finished, otherwise it might not work.
Once it is done installing, open up one of your saved games and there should be a new quest named 'Knothole Island is Freezing' or similar.