Hi!
The pcb layout in the second image has 16 buttons, 12 are for the notes (go from D6 to A3 or D13), 2 for pitch up/down and 2 for octave above/below (D2 to D5), which is how i mounted a protoboard
All 12 notes play and start in C4 to B4 but any of the 4 buttons for the pitch or octave do nothing, allegedly the code covers those 4 buttons and 2 potentiometers shown in the pcb layout connected in A4 and A5
i think the issue is in the code as nothing happens in the serial monitor or plotter when the buttons for pitch and octave but it does with the note buttons