I just got one of these and installed it: https://www.amazon.com/gp/product/B06Y3KL5P5/
. Pretty easy to install one of these once you have a level, 14"x14" square opening in your roof. If you put the fan along the centerline of the roof, the curvature will be minor enough that you can just cut the opening and screw the fan into place. If you want it off to one side, that's more complicated (I just did all this myself last week, it's on my build thread).
Wiring it up is super-easy. It's just two wires, and all you need to do is route the wires to wherever you have a 12V battery or an AC-DC converter (you'll probably need to attach extension wires since the ones from the fan are only a few feet long).