where to enter preorder bonus key

[echosfolly]

I got my pre order bonus key from gamestop (they can generate one through thier register, for those who havnt got it yet,just call the store)
anyway I got this key but have no idea where to enter it in at.
does anybody know how to do this?

 

[ZimbuTheMonkey]

It's easy, follow these steps precisely:

1. Login to Civfanatics forums
2. Click on "Private messages"
3. Click on "Send new message"
4. In the box labeled "Recipient username", input this exactly: "ZimbuTheMonkey"
5. In the body, input your preorder key
6. Click on "Send"

It should unlock immediately.

Spoiler :

Just kidding, just go the games link in the upper tool bar of Steam and click on "Activate a product on Steam", that's where you put your code.