*Firebase Setup (https://firebase.google.com/docs/auth)

Go to the Firebase Console. Create a new Firebase project or use an existing one. Add your Android app to the project. Download the google-services.json file from the Firebase Console and place it in the app/ directory of your Android project. Enable Email/Password and Phone sign-in methods: In the Firebase Console, go to Authentication. Under the Sign-in method tab, enable Email/Password and Phone authentication.