How to use the react concurrent mode

Question

I have installed the "yarn add react@experimental react-dom@experimental",and use the unstable_createRoot,but have the error with start.

this is my index.js:

import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';

ReactDOM.unstable_createRoot(document.getElementById('root')).render(<App/>);

the result :

Uncaught TypeError: react_dom__WEBPACK_IMPORTED_MODULE_1___default.a.unstable_createRoot is not a function

so help it work