Warren,
Here is a supply list:
1. Juniper/cedar branches or Ash branches in 4 feet of lenght or so.
2. Trotline twine - one spool
3. A sharp pocket knife per each child which they bring
4. Chainsaw file
Peel the branches,sand, file nicks for the string, find the center of the bow and mark it with a pen, pencil or marker and this can be the nocking point on the string, twist two strands of twine for your bow string, adjust the string so that your brace height is 4-5 inches.
Put the string on the bow and shoot. That's it. You can paint them and decorate them prior to finishing or after.
I once made 16 such bows like this once for my kids and neices and nephews. They fasted an arrow well and the kids had the best time ever. My children still have these bows in their rooms.
This is a hands on lesson or project that creates a functional working bow that can enjoyed by kids for years.
Hope his helps.
Cipriano