What to do If you win
Here’s Blizzard’s detailed instructions on what to do if you’re lucky enough to win a key:
Diablo III Beta Test Invitation (Key Claim)
Getting Started
1. Log in to Battle.net.
2. Click on the “Account” button.
3. Select the “Add a Game” button.
4. Enter your Diablo III beta key and select the “Activate Game” button.
5. Verify your age.
6. Select Windows or Mac as your operating system to download the beta client.
7. Select “Run” when the installation .exe pop-up box appears.