Install and build your first React Native app

React Native lets you build mobile apps using only JavaScript. With React Native, you don't build a "mobile web app", an "HTML5 app", or a "hybrid app". You build a real mobile app that's indistinguishable from an app built using Objective-C or Java. React Native uses the same fundamental UI building blocks as regular iOS and Android apps. You just put those building blocks together using JavaScript and React. React Native lets you build your app faster. Instead of recompiling, you can reload your app instantly. With Hot Reloading, you can even run new code while retaining your application state

1. Install Node
   mkdir ~/.npm-global
   npm config set prefix '~/.npm-global'
   export PATH=~/.npm-global/bin:$PATH
   sudo apt-get install -y nodejs
   npm install reinstall -g
2. use npm to install the create-react-native-app command line utility: npm install -g create-react-native-app
   
3. Run the following commands to create a new React Native project called "AwesomeProject"

   react-native init AwesomeProject
   
   cd AwesomeProject
   react-native run-android-android

React Native is like React, but it uses native components instead of web components as building blocks. So to understand the basic structure of a React Native app, you need to understand some of the basic React concepts, like JSX, components, state, and props. If you already know React, you still need to learn some React-Native-specific stuff, like the native components. This tutorial is aimed at all audiences, whether you have React experience or not.

Source: React Native CLI Quickstart