1. Need to start a new project and install the dependencies
2. To generate a new project choose the blank template depending upon the device used
3. Setup the firebase, the cloud service supported by google to handle authentication and database storage
4. Now, create a chat screen with a new directory as components
5. Connect the react native chat app with the firebase
6. Add the login screen to the chat app and add the functionalities and get it ready

Read more on React Native Video Chat App,
https://www.contus.com/blog/how-to-build-a-react-native-video-app/