I expected this to be quite complicated and therefore thought I'd need practice before starting. This turnout is the best and most flawlessly operating turnout I have on my layout.
Instructions Solder a small screw to the underside of each movable stub rail.
I did use metric 1mm screws, but anything small enough to be hidden under the rail's base should work. Using screws with a tapered head will allow sinking them into the tie more easily. Carefully mark two holes on the tie, with the distance exactly your gauge. Drill slightly larger than the screws you soldered to the rail. Countersink with a larger drill so the screws soldered to the approach rails can be sunk into the tie.