From the Super Mario Wiki
The event is a versus event, in which players compete in eight one-on-one rounds, the platform the players stand on rising after every two rounds. During each round, two competitors go against each other to see who can earn more points by pushing a series of buttons in order to do routines. Players who are not competing can clap to the beat of the music to earn more points.
In this event, 2 players compete in each jump to earn more points with their aerial routines.