MVVM (Model-View-ViewModel) is a clean way to write WPF application. While it's not part of WPF per se, it is used by many WPF developers, especially for large application. In short it keeps a clean separation between your C# and XAML code.
In this course, you'll learn about the basics of MVVM and will write MVVM commands. Once you master MVVM, you'll use it for unit testing. Finally, you'll write a file explorer from scratch in WPF - don't worry, you'll get plenty of guidance for this.
To attend this course, you should be very comfortable with WPF data binding and data templates.