Good question! There are blueprints for a lot of things online, but houses and buildings are a bit tougher. You could try finding one you like on a website like this:
https://www.homeplans.com/
http://www.perfectlittlehouse.com/designs.php
https://www.houseplans.net/
While I can’t recommend using their images as your exact blueprints, you could use a combination of them for reference about the scale and general placement of things without worry.
Hope that helps!
