I am developing a simple WPF application and I can create a single MainWindow with controls, content, etc.
However, I want to split my app. And I have a problem to build an app with welcome screen where user can choose between two modes, as seen below:

After click on Learn button I want to load this XAML:

And after click on Next (from Learn screen) or Recognize (from Welcome screen) I want to load this XAML:

...everthing in the same MainWindow.
I can't even name what I am trying to achieve. Do I want pages? Or views?
How to handle this situation in WPF ?