How does intake and exhaust in grow rooms/boxes work?

I can't find any info exhaust and intake, I'd like to know how fresh air can be brought into a grow box lets say. I'm guessing any box needs 2 holes, 1 to bring in fresh air and one exhaust to let stale air out, a fan in the box obviously pushes the stale air out but what is bringing the fresh air into the box? And also where should these holes be located on a rubbermaid grow box, exhaust and intake on the sides or exhaust on the top or jsut personal preference? thanks

well u have the right idea... u need 2 holes// one in, one out.... if you have a strong enough fan blowing air out of the grow chamber u will naturally have fresh air being taken in at the same rate ( if there is air blowing out that air needs to be replaced, and air doesnt appear out of thin air! haha) .. so cutting a hole to allow intake is important... the holes should be located on opposite ends of each other ( the intake will be low to the ground as it needs to take in new, fresh, cool air ) ... heat rises so u want to exhaust from the top.. u should have some sort of fan to help this process... check out my grow journal to get some ideas.. i also had some problems with this, but i worked them all out and made a journal detailing every step.. leave some comments while your checking it out! hope this helps ((reps appreciated))