Hi Mike
One of the biggest challenges with the very young is holding their attention, I have found an hour is enough for most. Whereas older children and adults can spend a whole lesson working on one aspect, I find the very young get bored so I split the hour roughly as follows: 10 mins warm up, 15 mins line basics, 15 mins kata, 15 mins partner work and 5 mins cool down. Obviously this is not rigid, but you get the idea. Some instructors advocate playing games with them, I personally do not. I am not saying those that do are wrong, just that it is not the way I do it.
You have to remember that they have no idea how to behave in a dojo, but they do know how to behave in a classroom. Point out in the beginning that it is very similar (ie put your hand up if you want the teacher's attention, don't leave the room without permission, no chatting etc.). I find it helpful with a new class to teach them one or two dojo rules per lesson and ask them about it the following lesson, praising them if they have remembered, reminding them if they haven't.
Young children often don't know left from right, remember to indicate which is which everytime you say something like "step forward on the left"
They often misunderstand instructions. A prime example is step forward and punch. Some young children "shuffle" forwards. If they do, try saying "walk forwards"
Young children do not take criticism well so rather than tell them they are doing it "wrong" I tend to say something like "I can see how hard you are trying and you have improved a lot. Now if you just do this it will be even better" Save cirtcism for misbehaviour if you can - it will have more effect.
I never tell a child they cannot go to the bathroom, but whilst they are getting changed I do remind them all to go before the lesson begins. If they ask to go during the lesson I say yes, but remind them that they should have gone before the lesson.
Lastly, at some point you will have to deal with a badly behaved child (or several
) Each instructor has his/her own approach to this but this is what I have found works best. First offence that lesson I tell them their behaviour is unaceptable. Second offence I make them sit on the side (only for a very few minutes). I then ask if they would like to sit out the remainder of the lesson or join back in. The answer is usually join back in and they behave the rest of the time. If there is a third offence they sit out until their parent comes to collect them and I speak to the parent and child together about it. On the very rare occasion I have to speak to a parent twice in the same month I ban that child from class for a week. This has only happened around half a dozen times in over 8 years of teaching (and I teach children 4 times a week) and I have only ever had to permanently exclude three people, one of whom was an adult.
The foregoing are just my opinions, I hope some of it is useful. Good luck.
Sharon