Redeeming a Playstation Network key is really simple, just follow these steps:

1. Go to this site: LINK
2. Click "Manage Account" and sign in to your account.
3. Click on "Redeem Prepaid Card". 
4. Enter the code and press the "Redeem..." button to add the item or funds to your account.

The key is not working

If you have activated the key according to the guide but the code appears not to work, please check what type of error message you receive and depending on it follow the appropriate instructions: 

• My key is Duplicated / Already used
• My key is Invalid
• My key is region locked / can't be activated in my country
• My key activated a different product
• My key did not activate all of the content