Getting Started

I'm doing some research on lighting systems for a HS and wanted to get some information. The school currently uses a basic ETC console but we are looking to migrate to HOG 4 PC. Other than the obvious software, what HES hardware is needed to interface with all the dimmer packs and Intelligent DMX fixtures? Apologies if this is a newbie question but when it comes to HOG I'm a newbie. We will eventually engage a lighting contractor for this but I want to understand the architecture. Thanks