- Launch the Steam client software and log into your Steam account.
- Click the Games Menu.
- Choose Activate a Product on Steam...
- Follow the onscreen instructions to complete the process.
Important:Ensure that you are activating your game through the Steam application. The Steam website cannot be used to activate a game. If you have not yet done so, you can download and install the Steam application by clicking on the green "Install Steam Now" button here: