Thanks for buying the asset!
I created NixFX_Lighting_System_Core because some people were having issues importing the demos into their projects. This yymps file contains only the core necessary scripts and objects to get the lighting system working, minus the demo assets. I'll update the documents to reflect this soon.
The Quickstart.md is located in the full NixFX_Lighting_System.yymps file under /datafiles/Quickstart.md and /datafiles/GettingStarted.html. If you don't want to import the full project, you can open this file like a .zip file by just renaming it .zip.