This article provides additional resources and samples for adding an MVC controller to the Alloy Demo site.
Get started developing with CMS - Requires some basic knowledge of building .net websites
Episerver CMS 9 tutorial with asp.net - tutorial with MVC 5 and bootstrap
Episerver CMS 9 documentation - General documentation
Introducing Alloy Demo Kit
AlloyDemoKit Repo - A github project with additional features and demos.