I just had it lying around.
Of note, I did do a cursory google search at one point but there weren't many good answers, or people asked the question and didn't get a response.
I finally found a thread to follow in a reddit post somewhere and I just registered the game via Stardock's website. Once you do that you can download the latest version, and then you'll have to go through the normal registration process once the game boots up.
