Each of the pages for setting up an editor/IDE has a simple "hello world" type of tutorial that creates a button and adds a listener. For example, here's how to get started with Visual Studio Code and HaxeDevelop:
Obviously, that's not in-depth at all. So, once you get an environment set up, your best bet is probably to take a look at some of the sample projects:
There is a sample that creates a login form, which doesn't actually do anything but clear itself when submitted, but at least gives you a slightly more complex view with a layout:
This next tutorial teaches how to creates a StackNavigator component and pass data between a couple of views:
I think that this is where you can start seeing how a more complex project should work (at least in terms of navigation).
A larger sample project that is more representative of a real-world app is definitely on my TODO list for a future update.