Arcane University: NPC Packages
The Beyond Skyrim Wiki — Hosted by UESP
AI-Packages (or NPC-Packages) control the behaviour of the actors in Skyrim. They specify where an NPCs works/eats/sleeps, how he behaves in combat or when he discovers a dead body.
See the known issues section for common issues at the bottom when working with NPC-Packages.
Getting Started
To get an introduction, make sure to read: Bethesda Tutorial Packages(Creation Kit Wiki)
Debugging Packages
Debugging AI-Packages is a cumbersome task to do, but there are tools that can help you with it.