aaaaand - if MIDI.read just gives you the raw MIDI data, you'll need to look up the protocol in the MIDI spec (been around since before the internet).
General approach will be to filter out the note information from the packets - i.e. some kind of conditional check on maybe the first byte (whatever the protocol is...) - then know how to extract the actual note from the rest of the packet - might be very simple, as in the bytes are simply the numbers themselves, or maybe the data is efficient (or inefficient 
) and spread over multiple bytes and you'll have to use bitwise operations. Maybe MIDI.read is half way there, it does some of the above, but you still need to tell it, what you're interested in...
BUT, you're going to have to do some of the work 
Bitwise operations although pretty simple are perhaps a little heavy going to learn if you're new to this - do you understand binary, does 'MSB' mean anything to you?
No worries though, we're here to help 