I got lucky because I started before most of that existed. :) But really, I think create-react-app is a great place to start. It has everything set up for you that you need and you never have to worry about it. Write ES6, explore React, and go from there.
After that you can try TypeScript or Flow. I'd recommend choosing whichever fits the best for your current app. Depending on the libraries you are using one of them might be more supported.
But really, just get started! If you don't know where to start, just load a JS file in the browser and start with vanilla DOM APIs. You will learn a lot and then you can make choices based on that experience.