I really enjoyed this photo due to its composition and the lights in it. The background light helps the image pop out by putting highlights around the figure. The key light helped by filling in the shadows to the face which created more highlights. The main light helped by giving the figure a good amount of light on it. I just like how this composition works overall.
The main light and the key light are the same thing. In this case, the main or key light was on the left. It makes the shadows. The fill light brightens the shadows. the background light creates separation between the subject and the background which is more or less what you wrote.