Your Steam Gift Card can be redeemed in just a few simple steps:

1. Login to your Steam account;
2. First click your account name in the top right of the site, click Account details;
3. Click Add Funds to your Steam Wallet;
4. Click Redeem a Steam Wallet Code
5. Enter the Steam Gift Card code that you received in your email;
6. Click Continue.

Note: that if you have never used Steam Wallet credit on your account before, you may be prompted to enter your current address in order to determine the correct currency.