Login to your Steam account
Click "ADD A GAME..." in the bottom left
Click "Activate a Product on Steam..."
Click "NEXT"
Click "I Agree"
Enter you game code and click "NEXT"
Proceed with installation by double clicking the game in your library.
Steam Key Location: You can find the option to enter your Steam key under the "Activate a Product" section in the desktop client.
Steam Key Issues: If your Steam key isn't working, ensure it’s entered correctly, check if it's region-restricted, or confirm it hasn’t been used before.
Mobile vs. Desktop: You cannot redeem a game key through the Steam mobile app. You must use the desktop client to activate the key.
Error Handling: If you get an error after entering the key, double-check the key, try again later, or contact Steam Support for assistance.