Can I implement TwoButtonPopup using ElmSharp?

I’m working on a Galaxy Watch widget.
The project inherited WidgetBase.

And I tried Xamarin.Forms’ TwoButtonPopup.
But I received this error message.

“You MUST call Xamarin.Forms.Init(); prior to using it.”
I am a beginner in creating a widget and this environment is very difficult.

The code on this site did not work.
http://tizenschool.org/tutorial/117/contents/12

Please help me.