I think he is trying to say:
If you move your mouse further up the frets (push your mouse up the screen), the chords get lower. The opposite effect for down, so the chords get higher. Maybe the chords should consist of the most basic and common:
A, B, C, D, E, F, G and any extra minor notes.
If you click while in this vehical, the sound will play, depending on the cursor position.
^^^^^
Is that what you were trying to say?