To execute the mobile app, you need to set up the development environment: https://reactnative.dev/docs/environment-setup
Once done it, open the PowerShell and type from the project root directory npx react-native run-android and npx react-native run-ios
Also, you can download the APK to execute the mobile app. This file contains all the necessary data to run de application.
To download de APK, go to release/app-release.apk