I just grab the dots with the mouse and drag them around, looking at how it affects the figure as I do so. You can also use the dials, for more fine control.  What are you asking? Just how to move them, or is this a survey?

My light sphere is on the left, but you can move any of this stuff anywhere on the screen (even the 'watermark' in the background of some versions..;)

I wish I'd said that.. The Staircase Wit

anahl nathrak uth vas betude doth yel dyenvey..;)