Place it over the entrance. When the swarm comes out, the workers go through the excluder, but the queen can't. She will find her way up through the little cones. There she is trapped. Pick it up and the swarm will follow it. Place it on the entrance of an empty hive and slide the little sheet metal out from over the opening. She will go down and into the new hive.The workers will follow. When she has eggs and larva, remove it and they will stay.