Step 1: Install all dependancies

using npm -

npm install

Step 2: Start your Application

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:

For Android

# using npm
npx react-native run-android

For iOS

# using npm
npx react-native run-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.