If you don't know how to teach, then you probably shouldn't be teaching... at least not with students that are so young. Maybe you shouldn't have taken up the offer if you didn't feel comfortable teaching, yeah?
But if you're going to do it anyway...
-Start with the basics; play a note on the headjoint, put the instrument together properly, correct hand position (this is a huge point that you may even want to spend the majority of a lesson on), correct posture, etc.
-Teach them a few notes. Maybe 2 or 3 a day. Then you can add on each day, and review a bit as well. You have to make sure they don't just forget what they learned previously.
-You'll want to spend time teaching them to breathe properly.
-And spend some time with tonguing.
-And embouchure.
-Why play along on the piano? You've got a flute, and that's what you're teaching, so play along on that.
There's so much basic information that you have to teach before you move on to tunes or scales. Maybe you should see if you can get someone older and more experienced with teaching to come and help you out. Even if you've been playing for 9 years, teaching is a completely different ballgame, and since you don't know how to teach you'll have a hard time getting anything accomplished with such a large group of such young students.
So yeah... I hope that helped you some.
