I help teach kids through a (partially) state funded program at a local shop each winter. It is alot of fun.
Anoited Archer brought up a good point. Finger protection, and arm guards are a must. Boys are boys, and girls are girls. The boys can whack their arm and blow it off, not so with the girls.
I recommend having someone there to help you when
the shooting starts. Just extra eyes if nothing else. All the history and technical data is great but they are gonna want to shoot. Get balloons.
Show them the basics of good form and they will take it from there. If they have trouble with the arrow wandering off the shelf or rest, have them try drawing three fingers under, this seems to help.
I have found that the boys already know it ALL.
But the girls seem to listen to your instructions
and they will get it fast. Good luck.