Open the Steam client or go to the Steam website
Sign in to your Steam account
Click your account name in the top-right corner
Select “Account details”
Click “Add funds to your Steam Wallet” or “Redeem a Steam Gift Card or Wallet Code”
Enter the Steam code exactly as shown
Click “Continue” or “Redeem”
Confirm the code and complete the process
Check your Steam Wallet balance or library for the added content