Use these 3 steps below to redeem the Steam Wallet Code:
Step 1: Log in to your Steam account > Under Account details, click "add funds to your steam wallet" to proceed to the next page.
Step 2: Click Redeem a Steam Gift card or Wallet Code.
Note: If you have never used Steam Wallet credit on your account, you may be prompted to enter your current address to determine the correct currency.
Step 3: Enter the Steam Wallet Code copied from your SEAGM account. You can obtain your purchased code by going to your "My Cards", enter your SEAGM account password to retrieve the codes.
Step 4: The funds will be added to your account and be ready for use to buy games on STEAM!