This series is also from my days with Falafel Software; we even published into a physical book we sold on the site, my first official publication! I still have a copy in my library, and I'm very proud of it.
Although a lot has changed since 2015, UWP and XAML are still a thing, so there might be a few helpful tidbits here and there. Do let me know if you find anything useful!
This is something I have been wanting to get back into ever since, so do watch out for an updated series on cross platform apps, exploring different options like MAUI, Uno, and Blazor in the near future!