No replies within 30 minutes is hardly being "ignored." Be patient.
Anyway, installing a fan is really easy in theory, but in practice you can run into some errors. Simply put, you just need to do as you said, cut a hole, screw it in, plug it in, and you're done. The cutting is done best/easiest with a hole saw. Drill some pilot holes for the fan screws. You honestly don't need to put a grill on, but if you have people/pets in the house that may be dumb enough to stick their fingers in, it'd be good to put one in. Unless you have a rheobus/fan controller, you just have to find a 3-pin connector on the motherboard to plug the fan in. Piece of cake, right?