How I did this would depend on the building I had. I have done it 20x ways. If I wasn't in biz and painted occasionally wouldn't have a booth.
But,,,,,,,,,,,,,,,,, read this.
http://finishingacademy.com/training/aero/aero_mod3/aero_mod3_intro.html Read all of it, about 10 pages. There is a fundamental difference between a booth and a clean room which seems to be confusing. With the right design you can run heating equipment in other part of non booth area.
I fire my wood stove hard before paint work, pulls warm air in to booth.
The thing about painting and vent is that there are fundamental principles about like electrical grounding. Once you master the principle it becomes almost reflex to match in and out to make air move.