Please select either public or private race when you have selected a video to train on it. Pick up one of these modes :
-Public race : initiate or join a workout and let other users join or leave whenever they want.
-Contest: Initiate or join a private workout with other users you know, everyone starting at the exact same time.
Third mode is Private race to start your own ride/run, on your own. Ghost to follow will be the one who recorded that video first.
To display on a larger screen, connect one device using AV hdmi adaptor or any AppleTV/Chromecast. You will see one rider/runner/rower icon user, going up and down on the elevation profile, moving on the map etc.