Exercise 1: Hello World with Expo App

Step 1: Environment setup

Setup the environment

Step 2: Start development server

In Terminal, run
```
npm install
npm start
```

Step 3: Use Terminal to sign in to Expo service

Sign in to expo with your laptop (press s in Terminal).
Restart the development server: Press Ctrl+C in Terminal and type
```
npm start
```

Step 4: Open your app

Open the Expo mobile app and check the projects tab. It should have your project listed there.
Open the app and you should see the text "Hello World!".

Step 5: Update code

Try then the live reloading feature: edit the text in ./src/index.js. Remember to save the file.
Your changes should be loaded automatically in the mobile app.

Step 6: Close app

Shake the device to see the Expo client app menu and navigate back to home menu.

Great, it seems you are now a mobile app developer! Now you can move on to exercise 2.