Flight instructor here. It usually takes 5 or 6 flights for students to become comfortable working the startup and shutdown procedures. By the tenth time they climb in the plane I can normally say “okay start up and let’s taxi out” and that’s detailed enough instruction for them.
It takes about 6 to 8 hours of practice flying the plane, from straight and level flight, turns, climbs, descents, slow flight, stalls etc. before I even try letting them land, and then usually another 6 to 8 hours of practice before they can put the airplane down gently more often than not.