How to open specific page from OneSignal notification in Flutter with go_router?

Question

I'm using the go_router package for routing in Flutter App. And we are using OneSignal for notifications. I'm using this handler when the user tried to open a notification

OneSignal.shared.setNotificationOpenedHandler(
    (OSNotificationOpenedResult result) {
  OSNotification payload = result.notification;

  print('"OneSignal: notification opened: ${result}');
});

I tried solutions from other answers but it's not working. My first question was, where to put this code in the app, Do I need to put it inside main function or here in Material App?

MaterialApp.router(
    routerConfig: router,        
  ),

And how to open a specific page in this case? Do I need to implement some listener inside go_router and listen to some state and that state will be updated when the user clicks on the notification, is that solution?