Unable to get past the 'React App' main screen - reactjs

Question

I'm not able to get a 'react' application beyond Screen with the "atom icon" and "learn React" link.
There is a message saying 'Edit src/App.js and save to reload.'
But there's nothing giving any information or clue about what changes need to be made to the App.js file, what configuration or other settings to check (and what the values should be), etc.
What do I need to do to get a React app to actually work?
//=========================
// BEGIN App.js SourceCode:
// ------------------------
import React from 'react';
import logo from './logo.svg';
import './App.css';
function App() {
return (
<div className="App">
<header className="App-header">
<img src={logo} className="App-logo" alt="logo" />
<p>
Edit <code>src/App.js</code> and save to reload.
</p>
<a className="App-link"
href="https://reactjs.org"
target="_blank"
rel="noopener noreferrer"
>
Learn React
</a>
</header>
</div>
);
}
export default App;
// ----------------------
// END App.js SourceCode
//=======================

Answer 1

The changes you need to make to App.js is the code for the initial page of your React App.

Answer 2

Replace your code with this, and change the "Hello":
import React from 'react';
import logo from './logo.svg';
import './App.css';
function App() {
return (
<div className="App">
<p>Hello</p>
</div>
);
}
export default App;