Here's a quick drawing for you. It shows how the ESPLux would be connected to a downlight.

Of course, the input can be a standard 12-24v power supply (both AC or DC), and the light could be any type of LED or incandescent globe. I've tested up to about 20w with no issues. 30w and the rectifier starts getting a bit too warm for my liking. I've found some parts on http://parts.io that I can replace the rectifier with, that'll be my next task after getting this batch of boards back.