Setup turtlebots as found on noetic docs, setup docker image on server
On server:
roscore
on turtlebot1:
ROS_NAMESPACE=turtlebot01 roslaunch turtlebot3_bringup turtlebot3_robot.launch multi_robot_name:="turtlebot01" set_lidar_frame_id:="turtlebot01/base_scan"
if turtlebot2, on it:
ROS_NAMESPACE=turtlebot02 roslaunch turtlebot3_bringup turtlebot3_robot.launch multi_robot_name:="turtlebot02" set_lidar_frame_id:="turtlebot02/base_scan"
wait for them to fully launch...
Back on server:
roslaunch turtlebot3_navigation robots.launch