How to clone create-react-app and run locally?

Question

React

Good afternoon.
Just started learning react.
At home, I created a project using the create-react-app command.
https://github.com/facebook/create-react-app

Changed the start page in App.js.

import React from 'react';
import './App.css';

function App() {
  return (
    <div className="App">
      <h1>Hello world!!!</h1>
      <p>Lorem ipsum dolor sit amet, consectetur adipisicing elit. Ab aliquid, consequuntur culpa explicabo in placeat quam unde! Consequuntur dolorem soluta tempore? Ab alias dolore est odit quidem saepe sequi, vitae!</p>
    </div>
  );
}

export default App;

Created a repository on github and pushed the project.

I cloned the project at work.
Installed create-react-app globally.
I went into the folder with the project, ran the commands:

npm init
npm install

Then I launched the project through yarn start

But there are no changes in build.

I did not find any information about cloning on the documentation site.

Or did I search badly?