Press PLAY, the cadence will play in the selected key.
Select the amount of notes that play after the cadence.
Play back the notes you hear after the cadence with the keyboard.
If you don't answer within the time limit, your answer is marked as wrong and your streak ends.
You can play with the computer keyboard. Type the note name and use Right Shift Key for '#' or Left Shift Key for 'b'.
You can also play with a MIDI keyboard on Chrome, Firefox, and Opera (Unfortunately not Safari)
When switching from "Play" mode to "Practice" mode, the options from the level persist. You can then adjust them to work on the level before trying again.