In this lesson, we'll get up and running with React Native while installing the extension for MacOS. For current instructions, head over to the React Native for MacOS documentation site, which will point you in the direction of the latest version: https://microsoft.github.io/react-native-windows/docs/rnm-getting-started.
To run your new Mac application, run
npx react-native run-macos. The first time you run this, it will take quite a while because project dependencies are being installed, but subsequent runs will go much quicker.