Add more comments and a note.

Author: maratal

src/pages/docs/push/getting-started/react-native.mdx

@@ -239,6 +239,7 @@ Push notification activation in React Native requires obtaining an FCM registrat
 
 <Code>
 ```react
+// Generate a unique device ID for this installation
 const [deviceId] = useState(
   `push-tutorial-${Platform.OS}-${Math.random().toString(36).slice(2, 9)}`,
 );
@@ -250,13 +251,15 @@ async function requestPermission(): Promise<boolean> {
     const settings = await notifee.requestPermission();
     return settings.authorizationStatus >= AuthorizationStatus.AUTHORIZED;
   }
+  // On iOS, request permission using Firebase Messaging which will trigger the native iOS permission dialog
   const authStatus = await messaging().requestPermission();
   return (
     authStatus === messaging.AuthorizationStatus.AUTHORIZED ||
     authStatus === messaging.AuthorizationStatus.PROVISIONAL
   );
 }
 
+// Save the device registration with Ably using the FCM token
 async function saveDeviceRegistration(token: string) {
   await realtime.push.admin.deviceRegistrations.save({
     id: deviceId,
@@ -329,6 +332,10 @@ After successful activation, `deviceId` contains the unique device ID assigned t
 On Android, use `notifee.requestPermission()` instead of React Native's `PermissionsAndroid` because it handles the `POST_NOTIFICATIONS` permission consistently across Android API levels. On iOS, `messaging().requestPermission()` shows the system notification permission dialog; Firebase Messaging calls the native iOS permission APIs internally.
 </Aside>
 
+<Aside data-type='note'>
+In React Native `realtime.push.activate()` is not used because it's a JS SDK and it registers browser for push notifications, which is not what we want in a React Native app. Instead, `realtime.push.admin.deviceRegistrations` API is used to register the device.
+</Aside>
+
 ## Step 3: Subscribe and test push notifications <a id="step-3"/>
 
 The FCM SDK handles background push notifications automatically and displays them as system notifications. For foreground handling, use `@notifee/react-native` to display notifications while the app is open.