10 Gather for a trip to Exhibit Hall. Prime students with appropriate questions. The coordinators do not and should not teach every subject. Your local NAIC Chapter has wonderful resource people. Coordinators should manage crowd control and troubleshoot technical and logistic problems.
Kids love scavenger hunts.
Make up one with the materials you have at hand. Make sure the bathrooms are nearby. Everyone loves recognition. Have some small prizes to toss when students give a great answer. Be generous with your praise and your prizes.