Learn each one on its own, by playing. You move a single setting, the photo reacts, and that is the whole lesson. Put all four together and you get the exposure triangle.
How wide the lens opens decides how much of the photo is sharp, and how much melts into soft, creamy blur behind your subject.
How long the camera looks decides whether a moving thing freezes pin sharp or smears into a streak of motion.
This brightens a dark photo, but push it too far and the picture turns grainy and rough. There is always a trade.
How far the lens reaches changes how close things feel to each other, and how flattering a face looks.