React neither is a framework, nor is it opinionated. When you're using React the time-honoured Perl motto TIMTOWTDI (https://en.wikipedia.org/wiki/There%27s_more_than_one_way_to... ) applies.

If you'd like a more opinionated, cookie-cutter approach there are frameworks such as Angular that fit that particular bill.

It's your job as a React developer to figure out these things. When people say React is simple, they usually mean that conceptually it's relatively simple. That doesn't necessarily mean it's easy to use.

That said, there are guidelines and tools like the following that can help you get started with your React projects:

https://reactjs.org/docs/faq-structure.html

https://github.com/alan2207/bulletproof-react/blob/master/do...

https://profy.dev/article/react-folder-structure

https://create-react-app.dev/

Your confusion is perfectly understandable, by the way. Having worked on web applications since the mid-90s I am what you might call a seasoned web developer, and at first I was confused by React, too. So, nothing to worry about.