# Usage After creating a Firebase project and installing the library, we can use it in our project by importing the library in our JavaScript: ```javascript import firebase from 'react-native-firebase'; ``` As the default app is pre-initialized natively there is no need to call `initializeApp` for the default app instance. Just import and go: ```javascript import firebase from 'react-native-firebase'; firebase.auth().signInAnonymously() .then((user) => { console.log(user.isAnonymous); }); ``` ### Configure Default App Instance ### Configuring RNFirebase