Need help with adding the code from the game to in order to play DIABLO II RESURRECTED.

When you purchase a game on your Bnet account it automatically adds the key. Then all you need to do is log in to the Desktop Launcher, download the game, and play.

If you were gifted the game in the form of a key you need to claim that key to your Bnet account.

At the top right of the website is your Battletag name and a drop down menu. Select Account Settings then you will see a box at the top to claim a code.