1. Bassoon Buttons: These buttons produce the lowest notes on the instrument, and are typically played with the left hand of the player.
2. Accompaniment Buttons: These buttons produce chords based on the notes played by the right hand melody buttons, providing rhythmic and harmonic accompaniment to the melody.
3. Melody Buttons: These buttons are played with the right hand of the player and produce the main musical notes of the tune being played.