Layman's guide to MAME LUA?

Hi folks, I was wondering if there were any good LUA guides for MAME for those who don't understand what it is all about*,
and what they can do with LUA and where to get SAFE plugins?

* This includes myself :)

ZX81v2

Here you go ZX, https://docs.mamedev.org/techspecs/luaengine.html

Wow Czokie, another one of those self fulfilling Questions...! lol