Get an app idea, and try and get to it by searching for any problems you run into along the way. Think logically, and it should get simpler after a month or two. I suggest you start coding in vb.net. It's simpler than c# and easier to learn, but once you're used to it, switching to c# will be way simpler.
Also, you need to get the basic ideas of how a program works.
You have the User Interface (UI), programmed in xaml, but Visual studio has a, um, Visual editor, so you don't really need to know xaml. The controls (all the things such as buttons, text boxes, switches, etc...) then "communicate" with the background code, that isn't part of what you can see. Each control has a set of events (for a button, things such as "pressed", which fire when you press the button) and you can associate these events with the background code. So for example:
Private Sub Handles Button1.Pressed
Textbox1.Text=("Button pressed!")
End Sub
Means that when you press Button1, the Textbox1 will show "Button pressed!"
I have done a very basic simplified explanation, but that will already help you quite a bit to get started. Good luck