Are there any guides or resources for creating a simple AI for a custom campaign?

I have noticed lately that many of the custom campaigns I have played and enjoyed lately have used what appear to be very simple AI to create units and move them around the map in a relatively intuitive fashion in B&D scenarios while also utilizing AI signals. Specifically, I've been thoroughly enjoying Bassi's Definitive Edition campaigns that he has uploaded so far and I'm incredibly curious if there are any resources, guides, or example AI that people know of to try and get the most out of simple AI scripts in custom scenarios. Any direction or advice would be greatly appreciated, as most of the searching I have done has lead to discussion about multiplayer AI, which I have little interest in exploring or making.