In the exciting visual adventure Mystery of Neuschwanstein, you will find all of the ingredients needed for a thrilling mystery adventure: a world famous castle, the mysterious, unexplained death of a fairy-tale king, and plenty of anonymous clues pointing to a whole web of dark conspiracies!
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