If the story has a crowd scene, everyone can participate. Otherwise, those without parts will be a very important part - the audience. Make sure those children have first chance at parts for the second run-through. For example, show them where Mount Sinai is, where the desert is, and where the camp with the people is. Keep the story moving without obviously directing the actors.
Special care is needed when introducing puppet activities to older children.
Try to schedule one of the Preschool or Kindergarten classes to see the performance at the end of the session. If a child is mishandling puppets or props, give him or her one warning, then have him sit in the audience. Explain that it is important to keep our equipment in good shape so that others can use it for a number of years. When videotaping, unless the cameraman is experienced, it is best to have a stationary camera and have the children orient their performance toward the camera. Play back the video and then let the children try again.