My advice is to be confident, you're not "maybe" an Assistant Director, you ARE the Assistant Director. You were promoted because of your hard work and your attitude, and you should be confident and convey that to your new staff.

You should not let the "power" go to your head, otherwise none of your staff will follow you, let alone campers.

I recommend the book "Super Staff Supervision" by Michael Brandwein for new supervisors on camp.