To move the light, drag the center circle.

To change the direction of the light, drag the handle at the end of the line to rotate the light’s angle. Ctrl-drag (Windows) or Command-drag (Mac OS) to keep the light’s height (line length) constant.

To change the height of the light, drag the handle at the end of the line. Shorten the line for a bright light, and lengthen it for a less intense one. A very short line produces pure white light; a very long one, no light. Shift-drag to keep the angle constant and change the height of the light (line length).