Mario, I can't play a keyboard but by using the multi track feature on my keyboards in the past, I literally used each track as a finger layering chords, riffs and melodies to get what an average musician plays with both hands. Tedious work. Years ago (in the early 90's) my daughter gave me a book of piano chords that was a great help. I practiced a chord change or riff long enough to get it recorded once. I recall having to stop my recording if I needed to look up how to make a Bm chord...
16 tracks of midi were a blessing.