"Wings" and "Immortal Edition" keys for Guardians of Ember are invalid

The "Guardians of Ember" key is a conventional Steam key - use it to add the base game to your Steam library in the usual way, as described here.

The "Guardians of Ember - Wings In-Game Content" and "Guardians of Ember - Immortal Edition" keys are NOT activated in Steam, they are instead entered within the game as follows:

1. Open the Steam client and start Guardians of Ember.
2. Log into the game.
3. Open the Frozen Ember Shop via the blue crystal icon located on top row of the screen.
4. Navigate to "voucher" on the left side of the shop window.
5. Insert the voucher in the top field and insert "0" in the bottom field and hit enter to unlock your items/version.
6. You will find your items in your inventory.