Sea of Thieves - Valiant Corsair Oreo Ship Set DLC Xbox Series X|S

Sea of Thieves - Valiant Corsair Exclusive Sail Set Oreo Skin - Xbox

Go to https://www.xbox.com

Login to your account

Hover over your account link (the top right of the screen) a menu will appear, click on the "Redeem Code" button.

On the next page, click "Redeem"

Enter your code

Click "Confirm"

Click "Confirm" again to assign the key to your account.