I agree about instilling respect ie. yes ma'am, yes sir, etc. I would go over the rules. Bowing as you enter and exit. No talking, no chewing gum, no running, no goofing around when you are told to do something. Ask permission to leave to go to the bathroom (so instructor knows where they are at and there is no line where goofing off can occur). Raising your hand for questions, or for help, and waiting your turn quietly. If it is a large class, an assistant instructor is needed.
After an explanation of the rules and the warmup exercises, then a fun active time. This could be races around cones, jumping over cones, monkey run, crab walk...these are to let out some of that energy too. If they don't remember it as fun, the parents would have a hard time bringing them back. After this, I would teach the basic kicks-front, round, side, and I would also teach long stance for their beginning form. If higher belts were there, they could practice their forms. At the end we usually do ab workout and stretches. TW