red sea max e-260 reef system 69 gallon

I have read several post about this but I am struggling to find the information that I need. We have a Red Sea Max E-260 and we would like to add a sump however we are not sure where to begin. We would like our sump to have a skimmer, a refugium, and a UV sterilizer. I have seen some sump kits...

Alas, due to life circumstances I am exiting the hobby and will be selling my reef systems. This post is for a 2-3 year old Red Sea Max E-260. 69 gallon. Black Stand, 2 AI Hydra 26HD lights, return pumps, skimmer and pump, 2 port doser, no heater. Tank needs cleaning as it has some dried...