*Please Note: If the handle you're using will not slide far enough into the female receptacle on the pad holder, there is a C-clip in the neck of the pad holder that can be removed. This allows your handle to adequately slide far enough into the receptacle that you can properly tighten it to hold onto the handle.
To attach to a threaded or unthreaded pole, start by disassembling that mop head. This includes removing the coupling from the head and removing the C-clip that is clipped into the shaft.
Put the plastic coupling on the pole. The coupling may be a snug fit but should slide on with a tiny bit of force.
Put the pole into the top of the mop head. A small amount of force may be needed to get the head on. You should be able to see the threads through the hole that the C-clip.
Screw the coupling into place. The pressure from the bracket should hold the head securely in place.