Awaking on an island with no memory, you have just one memento of the life you led before… A child's photograph. Who is this? You must search the island for useful tools that will aid in your escape. As time passes and hopes of survival hang by a thread, you realise that this island is not as it seems.
Open the Steam client, login and locate the Games tab on the top menu. Click this and then select “Activate a Product on Steam…”
Enter your unique code that's displayed on the 'Orders' page of CDKeys.com and follow the prompts to activate.
Your game is now viewable in the “Library” tab and is available to download/install when you’re ready. You can find additional support for the Steam client here: https://help.steampowered.com/en/wizard/HelpWithSteam