The Navigation Drawer application template within Visual Studio 2019 stops short of being a functional starting point. While a lot of the plumbing is in place there is no indication about how to respond to menu option selection, i.e. displaying different content views on demand.
This sample takes the default template a few steps forward to demonstrate a working implementation - there may be others and there maybe better but this one works for me.
More information on the creation of the template can be found in this blog post: https://onthefencedevelopment.com/2020/02/17/getting-started-with-visual-studio-2019-android-navigation-drawer-template/
If you have a better implementation or have a suggestion the please create an issue or a pull request - whichever works.