Connect MIDI keyboard to Arduino UNO via USB

How would one go about programming an Arduino UNO to read MIDI signals from a MIDI-keyboard connected by USB?

The project is to make a self-playing recorder flute that's controlled by an Arduino UNO and played by 8 servos and a centrifugal fan to provide air flow.

The machine is supposed to convert the MIDI signal from a keyboard and translate this into motor movement.

We need some pointers as to how we should go about programming this, assuming we have a USB-shield to receive the signals from the keyboard.

Any help would be greatly appreciated!