If you already own Dawn of Fantasy
then you can activate Dawn of Fantasy: Kingdom Wars
on Steam with your existing game key - no matter if you got the key from a giveaway, bundle or retail purchase, as long as it's a valid key, you can use it.
Here's what you need to do:
1. Open the Steam client
2. Click on the "Games" menu
3. Choose the "Activate a Product on Steam" option
4. Follow the instructions and agree to the Steam Subscriber Agreement
5. Enter your current Dawn of Fantasy game key
(without dashes) when prompted
6. Follow the prompts to begin installation
The game will then download and be ready for you to enjoy.
All your progress, towns, and achievements will carry over to your Steam installation, just log on in-game with your current username.
If you can't find your game key, you can use this page
to recover your it and/or password, just enter your in-game name or email address and it will send the details you need to the email address you registered your account with.
If you've still having problems, just reply here or email firstname.lastname@example.org