Do you want to create a mobile app or a website with React that works and it is responsive for mobile browsers?
If you want to create a mobile app, you need React Native instead of React.
React Native lets you create Android and iOS apps for the front end. You can use NodeJS for your RESTful API for example as the backend.
If that is the case, you can check this article – LINK – which the guy explains what you need to use NodeJS for your React Native application
If you want a website built with React you can follow this article – LINK – which the guy creates a simple CRUD app with NodeJS and React
CLICK HERE to find out more related problems solutions.