In this video you'll learn how to configure the swarm feature for multiple Tello EDU drones. It's necessary to have a wifi "router" or "access point" to enable this feature. We have been using the TP-Link N300:

https://amzn.to/2TR1r56

Feel free to reference the Tello EDU SDK document for additional information:

https://dl-cdn.ryzerobotics.com/downloads/Tello/Tello%20SDK%202.0%20User%20Guide.pdf

A link to the flow from this video can be found in GitHub:

https://github.com/dbaldwin/DroneBlocks-Tello-EDU-Node-RED/blob/master/12_node_red_tello_edu_wifi_config.json