use gazebo for the virtual simulation
rqt_graph will show all active topics in a gui
ros2 topic list will list all topics in the commandline
ros2 topic info <topic> will give details about a specific topic. One of the properties it returns is the interface type
ros2 interface show <interface type> will show the structure of the data that this type expects
After this, publish the data it returns to the topic:ros2 topic pub --once <topic> <interface type> "<data>"
you can substitute --once with --rate <number> to send the same message for an x number of times per second
ros2 topic echo <topic> prints all incoming messages
ros topic hz <topic> prints the frequency of incoming messages
use ros2_control to use a controller