It would depend on how much time you have to collect information and materials. You might post on Bowyers Bench, forum on this site.
You might ask for help, information, and materials, hand tools (loaned), and accept donations. It would be helpful to find someone in your home state, that has experience teaching kids the art of selfbows. Some wood is easier to work, but still needs to be air dried.
Vine Maple found locally, in WA and OR when seasoned (dried) will make a good kids bow.
Air drying is preferred to kiln dry lumber. Wood obtained through a lumber yard, is almost always kiln dry. Lumber is rough cut into boards and then finished, but the surface grain is almost always a problem for bowyers. It takes experience to locate and select suitable boards, and then the work starts. It does require a certain degree of skill to fashion a selfbow, and to teach others how to do it, with a limited amount of time.
I would start by looking for help from someone in your state. Try this forum, and The Bowyers Bench. Check for local shops, and clubs in your area.