Most learn at home. Firing a firearm accurately does require some practice and skill. Shotguns are the easiest, pistols are by far the hardest. In an enclosed space though it isn’t that hard to hit a human sized target. Most people who shoot guns probably know how they work. They aren’t all that complicated. Usually just safety, a mekanism to cock it, a trigger, and a magazine release. It doesn’t take that much training to learn how to shoot something a few feet away from you. It does take a bit to hit targets further away than say 25 feet. This is often why cops end up smoking gangsters. Many gangsters don’t practice with their firearms and cops do, so in a ranged fight, cops usually win.
Hitting a moving target is difficult. Most people don’t realize how easy it is to actually take down an armed person who isn’t skilled and practices things like the 30 ft rule which most cops will practice. (If you get within 30 ft, they will assume you can disarm them before they can land their first shot) Aiming usually takes a few seconds if you want to land your hits, even with a stationary target 25ft away. Some people practice a lot and john wick it, but real shooting is more like an entire body composure, carefully leveling the sights, squeezing, not pulling the trigger (rookie mistake) because if you pull the trigger too fast you will miss unless someone is very close to you.
I’m just a regular nonbinary person, I learned to shoot skeets out of the air before I hit puberty. I can throw up a soda can and shoot it with a shotgun. I practiced a lot and hunted a lot. (Not into hunting these days because I’m a different person, and love animals) I might if I were hungry enough.
Google really sucks now for some reason. It used to be much better.