HMVC the right way ?!

I am not understanding this. If you have an Auth Module, most likely every module in your app might require it.
Are you talking controller to controller calls or a view calling different controllers?

I really do not understand the correct way to use HMVC and would love to see a tutorial.

Yes, that makes sense to me. I have seen other HMVC tutorials where a view runs a module method to render a checkout form.
If I understand you correctly, HMVC should not be used then in favor of just creating libaries.