1. Visit the link: https://store.steampowered.com/account/redeemwalletcode

    - Before able to redeem the game code, it's compulsory to install Steam application. Click on "Install Steam". 

2. After the installation is complete, you may login like usual from the Steam apps that you installed. After login, please click on "+ ADD A GAME..." on the bottom left.

3. Again, choose "Activate a Product on Steam..."

4. After that, there is a new window will pop up. Click "Next".

5. Must choose "I AGREE" before you can proceed.

6. Fill in the code that you have purchased and click "NEXT". You will be receive a new message once the code is completely redeem.