After pressing start you will be given a text based score.
All players should press start simultaneously!

Allow your phone to use the camera. Frame another player with the camera with an extended arm.
Each performer selects a different person.
Keep the other player framed with your camera during the piece, play your instrument with your other hand.

New instructions will be given a few seconds before the status bar fills up and the screen flashes. Change to the new behaviour when this happens.