1. Head over to the Firebase Console.
2. Click "Add project" and just follow the instructions to create a new project.
3. Once you're done, go to the project dashboard.

1. In the Firebase console, go to "Project Settings".
2. Click the "General" tab, then hit the "Web" icon to add Firebase to your web app.
3. Register the app and copy the configuration settings (API Key, App ID, etc.).

1. Navigate to the root directory of your React Native project.
2. Install Firebase and its dependencies using npm or yarn:
   ```bash
   npm install @react-native-firebase/app @react-native-firebase/messaging
   ```

1. Create a firebase.js file in the project's root:
   ```javascript
   // firebase.js
   import firebase from '@react-native-firebase/app';
   import messaging from '@react-native-firebase/messaging';

   const firebaseConfig = {
   apiKey: "YOUR_API_KEY",
   authDomain: "YOUR_AUTH_DOMAIN",
   projectId: "YOUR_PROJECT_ID",
   storageBucket: "YOUR_STORAGE_BUCKET",
   messagingSenderId: "YOUR_MESSAGING_SENDER_ID",
   appId: "YOUR_APP_ID",
   };

   if (!firebase.apps.length) {
   firebase.initializeApp(firebaseConfig);
   }

   export { firebase, messaging };
   ```

1. In index.js or the entry file, import firebase and messaging:
   ```javascript
   import { firebase, messaging } from './firebase';
   ```

2. Request permission for notifications (usually in App.js):
   ```javascript
   import React, { useEffect } from 'react';
   import messaging from '@react-native-firebase/messaging';
   import { Alert } from 'react-native';

   const App = () => {
   useEffect(() => {
   const requestUserPermission = async () => {
   const authStatus = await messaging().requestPermission();
   if (authStatus === messaging.AuthorizationStatus.AUTHORIZED || authStatus === messaging.AuthorizationStatus.PROVISIONAL) {
   console.log('Authorization status:', authStatus);
   }
   };
   
   requestUserPermission();
   
   const unsubscribe = messaging().onMessage(async remoteMessage => {
   Alert.alert('A new FCM message arrived!', JSON.stringify(remoteMessage));
   });
   
   return unsubscribe;
   }, []);

   return (
   // Your app code here
   );
   };

   export default App;
   ```

1. Get the device token to uniquely identify the user's device for sending notifications:
   ```javascript
   import messaging from '@react-native-firebase/messaging';

   messaging()
   .getToken()
   .then(token => {
   console.log('FCM Token:', token);
   });
   ```

1. Create index.js in the root directory if it doesn't exist and add the following:
   ```javascript
   import { AppRegistry } from 'react-native';
   import App from './App';
   import { name as appName } from './app.json';
   import messaging from '@react-native-firebase/messaging';

   messaging().setBackgroundMessageHandler(async remoteMessage => {
   console.log('Message handled in the background!', remoteMessage);
   });

   AppRegistry.registerComponent(appName, () => App);
   ```

1. Open android/app/src/main/AndroidManifest.xml and add the following permissions inside the <manifest> tag:
   ```xml

   \`\`\`

2. Add the following service inside <application> tag:
   ```xml
   
   ```

1. Add the required keys to your Info.plist file:
   ```xml
   UIBackgroundModes

   fetch remote-notification \`\`\`

2. Make sure Push Notification capabilities are enabled in your Xcode project.

3. Register for remote notifications in App.js:

\`\`\`javascript
useEffect(() => {
  messaging()
    .registerDeviceForRemoteMessages()
    .then(() => {
      console.log('Device registered for remote messages');
    });
}, []);
\`\`\`

1. Make sure your app is running on a physical device or simulator/emulator.
2. Use Firebase Console to send a test message to the registered device and verify the notification is received.

These steps set up Firebase Cloud Messaging in a React Native app effectively. Always check for updates in case of any changes in library implementations or API updates.