To start a React Native application using Expo, you can follow these steps:

• Install Node.js and NPM: React Native requires Node.js and NPM to be installed on your computer. You can download and install them from the official Node.js website.

• Install Expo CLI: Expo CLI is a command-line interface that you can use to create and manage Expo projects. You can install it using the following command:

npm install -g expo-cli

• Create a new React Native project with Expo: You can create a new React Native project using the expo init command. For example, to create a new project called "MyApp", you can use the following command:

expo init MyApp

• Choose a template: Expo will ask you to choose a template for your project. You can select any template that suits your needs.

• Start the development server: Once your project is created, you can start the development server using the following command:

cd MyApp
npx expo start

• Run the app: You can run your app on a device or emulator using the Expo app on your phone or by opening the app in a web browser. To run the app in a web browser, click on the "Run in web browser" option in the Expo development server that you started in the previous step.

• Start coding: Your React Native app is now ready to be developed! You can start writing code in the App.js file and create components and screens as needed. You can use a text editor or integrated development environment (IDE) of your choice to write your code.

That's it! You've now started a React Native application using Expo and are ready to start building your app. Expo provides additional features and tools that can help you build and test your app more efficiently.