You probably have things backwards. You start by having products you want to sell, and then if you think Amazon may be the right way to sell it, then you try to find out how Amazon works, and that's where courses may be useful (or not).
There's no magic "I become an Amazon seller and I suddenly make money" formula. You need to find products to sell. You need to find people to buy them from. You need to buy them (i.e. pay them). You need to have the stuff shipped to Amazon. If it comes from abroad, you need to handle taxes and duties and be sure they comply with local regulations. You have to create your seller account. You have to create listings for all products, with pictures, description, all sorts of details. You need to select prices, and possibly adjust them constantly. You have to handle support requests. You probably need to do some advertising (either on Amazon or elsewhere) to bring customers in. And of course you have all sort of tax-related stuff on top of that, including probably setting up a company and a bit of accounting.
It's just a business like any other. A combination of a good idea, good execution, and hard work could make you rich. Or could swallow all your money if you're not prepared or try to sell the wrong product, or sell it at the wrong price or forgot about many of the small details that can make or break a business.
Amazon just simplifies a lot of things for you: it lets you relatively easily be present on one of the biggest stores in the world (if not the biggest), they will handle payments, they can handle shipping out to customers faster than you could ever do it yourself. But you'll be just one of millions of sellers, selling a few of the millions of products on the store.