Adding a new screens can be done in a couple of steps
Create a new folder, i call it new_screen
and place it under /lib/screens/
.
Create a new file new_screen.dart
within this folder.
class NewScreen extends StatelessWidget {. . .. . .}
Open the /lib/routes.dart
Add a new line like below
NB: I called my new route "new_screen"
//import the recent screen you created "NewScreen"'/new_screen': (context) => NewScreen(),
you can refer to your new route by "navigation" using the code below
Navigator.pushReplacementNamed(context, '/new_screen');