In order to redeem your Steam Wallet Code, you will need to create an account at steampowered.com. The quick link to this page is here: https://store.steampowered.com/join/
You will be prompted to enter your information; including your account name, password, and email address that you wish to tie the account to. Read through the terms and conditions associated with creating your account and finish the process. You will receive an email confirmation shortly afterwards.
After you have created your account, you will be able to add funds to your Steam Wallet by redeeming your Steam Wallet Code purchased here at TheCardWalla.
Congratulations! You now have access to all of the PC games, content, and gaming hardware that Steam has to offer!