Any good tutorial suggestions for how global or core/console specific settings work?

I’m looking for a good tutorial on setting up core specific settings, global settings and learning the ins and outs of that. Examples would be like setting up shader/video filters per core/console (ie: all snes games) or a good explanation of the levels and file location (global>core>game). Someone who not just explains how but also why with examples.

I’ve had to start from scratch too many times and really want to know what the heck I’m doing wrong. 😅