Instructions for activating the key:
1. Download and install Steam
http://steampowered.com/download/SteamInstall.msi , register an account on Steam.
2. Launch the Steam client, log in to your account and click "Add game - activate via Steam" and follow the instructions. After activation, the game will appear in the list of games and you can download it.
If you have any additional questions, contact the seller in an online chat or write to e-mail.
