Arduino UNO As A MIDI Keyboard

Projects Programming
27 
#include <Control_Surface.h>
#include <MIDI_Outputs/Bankable/NoteButton.hpp>
// Instantiate a Transposer that can transpose from one octave down to one
// octave up
Transposer<-12, +12> transposer;
 
// Instantiate a Selector to change the transposition
IncrementDecrementSelector<transposer.getNumberOfBanks()> selector {
  transposer,
  {M2.pin(9), M2.pin(10)},
  Wrap::Clamp,
};
 
// Instantiate an array of NoteButton objects
Bankable::NoteButton buttons[] {
  {transposer, 2, 48}, {transposer, 3, 49},
  {transposer, 4, 50}, {transposer, 5, 51},
  {transposer, 6, 52}, {transposer, 7, 53},
  {transposer, 8, 54}, {transposer, 9, 55},
};

The PBPotentiometer is working sooooooo goooooooood
but the transposition isn't functioning however the code is not giving any errors
and I want the two buttons on the right to switch between channels .. how can this be done ??