Before proceeding, you should select a target platform and run the application. For more information on debugging an application, see for Visual Studio, Visual Studio Code, or Rider.
The majority of an Uno Platform application is defined in a project, in this case, named Counter. This project contains files that define the layout of the application and files that implement the application logic.
The startup logic for the application is contained in the App.xaml.cs file. In the OnLaunched method, the MainWindow of the application is initialized with a Frame, used for navigation between pages, and the MainPage is set as the initial page.