Set Navigator Observer

In the main.dart file, change from

return MaterialApp(
      title: 'Flutter Demo',
      routes: {
        "/": (context) => const DemoScreen(),
        '/Screen1': (context) => Screen1(),
        '/Screen2': (context) => Screen2(),
      },
    );

To the below.

import 'package:vwo_insights_flutter_sdk/vwo_insights_flutter_sdk.dart';
 
return MaterialApp(
      title: 'Flutter Demo',
      routes: {
        "/": (context) => const DemoScreen(),
        '/Screen1': (context) => Screen1(),
        '/Screen2': (context) => Screen2(),
      },
      navigatorObservers: [
        VwoNavigatorObserver(),
        YourNavigatorObserverIfNeeded(),
      ],
    );