Name: Cthulhu Realms - Full Version DLC (Steam)
Brand: White Wizard Games
SKU: KT-A5FEB522EB
Price: 0.60 EUR
Availability: InStock

Upgrade to the full version and unlock eight new campaign missions, a more difficult AI, a local multiplayer, and perhaps most excitingly, a robust online multiplayer mode. Features Play the AI on 2 different difficulty settings. 8 more fun campaign missions. Battle your friends face to face with Pass and Play. Play against many more opponents online. Challenge a friend to online Player v Player combat

Redeem on Steam

You need a Steam account and the Steam app.

Step 1: Open Steam and sign in.
Step 2: Open the Games menu, then choose Activate a Product on Steam…
Step 3: Enter the key and follow the prompts.
Step 4: The game appears in your Library.

Steam's redeem page Full guide for Steam

Activation notes from the publisher

Go to: http://store.steampowered.com/ and download STEAM client Click "Install Steam" (from the upper right corner) Install and start application, login with your Account name and Password (create one if you don't have). Please follow these instructions to activate a new retail purchase on Steam: Launch Steam and log into your Steam account. Click the Games Menu. Choose Activate a Product on Steam... Follow the onscreen instructions to complete the process. After successful code verification go to the "MY GAMES" tab and start downloading.