in your lib/main.dart you can find all the screens defined as routes already. Whatever Screen is assigned to '/' is that starting route. In this case, the SplashScreen() will start first.
lib/main.dart
Widget build(BuildContext context) { return MaterialApp( initialRoute: '/', routes: { '/' : (context) => SplashScreen(), '/home' : (context) => HomeScreen(), '/detail' : (context) => DetailScreen(), '/login' : (context) => AuthTabScreen(), '/search' : (context) => SearchScreen(), '/forgot' : (context) => ForgotScreen(), '/slider' : (context) => ISliderScreen(), '/favourite' : (context) => FavouriteScreen(), '/story-highlight' : (context) => StoryHighlight(), '/profile' : (context) => ProfileScreen(), '/edit-profile' : (context) => EditProfilePage() }, debugShowCheckedModeBanner: false, ); }