To get the sound of a real instrument you need to get right:-
- the frequency
- the mix of harmonics
- the changing mix of harmonics over time.
- the change in all the above when the blow velocity changes.
There are two options, you can either play back a sample sound from a wave shield, one for each note. Or you can synthesise the waveform. The UNO is not fast enough to do this but it is possible to do this with a Due. There is a good book about modelling synths by Perry Cook, he has a web site with code on it to help you to do this. However it is not a thing for beginners, it is rather advanced.