Immediately, get the key immediately upon payment.

Reward Instructions: Congratulations on getting an in-game reward for Dune: Awakening. In order to claim the item in-game follow these steps:

Step 1: Go to duneawakening.com/account.
Step 2: Follow the steps to link your Steam account to your email.
Step 3: Navigate to "Redeem Key" on the navigation on the left-hand side.
Step 4: Enter the code where it says "Product Key".
Step 5: Click continue.
Step 6: Click confirm.

Note: You need to own any version of Dune: Awakening in your Steam Library for this to work.