When you originally bought the game from Introversion you were emailed a link to the builds. This link is re-sent to you every time we do an update so before you mail in, please check your in-box and spam filter for mails that have come from: Introversion Software <firstname.lastname@example.org>.
Your link will take the form:
If you have lost the link you can have it resent here:
By following that link you will find your steam retail activation key which will look like this: XXXXX-XXXXX-XXXXX
Copy it into the clipboard then from within Steam click “+ Add Game” -> “Activate a Product on Steam” and paste your key. Follow the instructions and Prison Architect will be added to your game collection and you’ll get automatic updates.
If you need your email resent then contact us at email@example.com and make sure you include the email address that you used to buy the game (this may be your paypal email address).