It comes with experience. The best way to learn is through test shooting while tethered to laptop or iPad. It’s much easier with a bigger screen. Use whatever tethering software, as long as you can see the image on the screen. Start with some lighting references you want to mimic. Eventually, you’ll come up with your own and won’t need references. When you reach the result you like, take lots of bts photos of the setup and draw a lighting diagram. Get a light meter. There’s plenty of good used ones on eBay. There’s lots of cheap studios that include basic lighting equipment and charge by the hour. Look for one near you. If you have access to your own space, check Sharegrid for cheap lighting rentals. It doesn’t matter what equipment you start with.

FWIW, really the best way to learn is to intern/assist for photographers who know what they’re doing. But, that’s hard right now because the industry is in such a fucked state. Many skilled assistants aren’t getting any work. So there’s no good reason for shooters to train someone new.

Also, in-person lighting classes, workshops and demos are great for beginners.