If you were playing the game log off Runescape, and also log off your Steam account. Log in to Steam with the credentials provided in an email you received after purchase or in your library on our store. Log into your Runescape account (using your own login and password) from the Steam account of the seller. You will see information: You have pending Steam packs. Would you like to apply them to this account? Click: Accept. If you're requested to Link to Steam economy - Decline Once you accept the Steam pack the content will be added to your Runescape account. After this relog to your Steam account and double-check the added content. DLC is not visible in Steam library, it will be visible in-game in Runescape.