The Freerooms mobile app uses Expo
You can run the following command to install dependencies:
npm install
In order to open the app on your phone, you will also need to install the Expo Go app.
You can run the app with the following command:
npm run start
This should generate a QR Code, which you scan with your phone to view the app. Make sure your phone is connected to the same WiFi as the machine that is running the server.