As specified in the previous artice (Installation), run the `Create React App` tool. After everything has finished, `cd` into the folder of your application and run `npm start`.
This will start a development server and you are all set to start developing your app!
Start up your editor or IDE of choice and edit the `App.js` file in the `src` folder. When created with the `react-create-app` tool, there will already be some code in this file.
To get started, edit <code>src/App.js</code> and save to reload.
</p>
</div>
);
}
}
```
React is a library that makes use of Components, which let you split up your UI into independent, reusable pieces, and think about each piece in isolation.
There is already 1 component created, the `App` component. If you used the `create-react-app` tool, this component is the main component in the project and you should build around this central class.
We will look at components more detailed in next chapters.
When creating a class in react, you should export them after declaration, which allows you to use the component in another file by using the `import` keyword. You can use `default` after the `export` keyword to tell React that this is the main class of this file.
```JavaScript
export default App;
```
### View the results!
When you've started the development server by issuing the `npm start` command, you can view the changes you add to your project live in your browser. After issuing the command, npm should open a browser automatically displaying your app.