question about ReactPackageProvider.idl for creating a native UI module

When following the Sample ViewManager (C++) part of this tutorial

https://microsoft.github.io/react-native-windows/docs/view-managers

I just want to create the native view using visual c++ and the first line in the ViewManager(C++) tutorial says

For this sample, assume we already have the CustomUserControl defined in the C# example.

How can I create a native C++ view for use only within my existing react native project and not to create an entire native module for use by other people.

It's also unclear to me if the example given in the tutorial is possible with no C# code which I was trying to avoid in favor of only C++.

The part of the tutorial where you are supposed to create ReactPackageProvider.idl seems like it would be only if I was making a module for use in multiple projects, which I'm not, so any clarification here would be greatly appreciated.

Thanks