You can use the shortcuts above the piano (A,W,S,E,D,F,T,G,Y,H,U, and J). Press the up and down arrow keys to change the octave by one. Press the left and right arrow keys to change the duration by 0.5 beats.
Working on a recording option that might come out in December. Default settings: octave: 4, duration: 1 beat(s)
