Activating a Steam key is really easy. Follow these short steps:

1. Open Steam, and sign in or log in to your Steam account.
2. At the home screen, click on the Games menu at the top left corner.
3. A drop-down menu will appear, then click on ‘Activate a Product on Steam…’.
4. A pop-up window will appear asking you to enter your product code.
5. After writing the code for your Steam game, click on ‘Confirm’.