A one-bar phrase in C major. Hear it, then sing it in time with the count-in — the mic grades each note for pitch and whether you sang it on the beat.
The rhythm tells the app exactly when each note should sound, so it listens in each note's time-slot and checks your pitch there — you can sing in any octave. Sing along with the clicks; aim within a quarter-tone and land each note on its beat. Pitch is graded octave-free, so high or low voices both work.