First, you will need to install dependencies and start Metro, the JavaScript bundler that ships with React Native.

To start Metro, run the following command from the root of your React Native project:

yarn install
cd ios && pod install
cd ..
yarn start

Let Metro Bundler run in its own terminal. Open a new terminal from the root of your React Native project. Run the following command to start your Android or iOS app:

yarn android

yarn ios

If everything is set up correctly, you should see your new app running in your Android Emulator or iOS Simulator shortly provided you have set up your emulator/simulator correctly.

This is one way to run your app — you can also run it directly from within Android Studio and Xcode respectively.

You've successfully run your React Native App. 🥳