If you look inside the insulator, you will see a ring slot nut. Uses a special tool, has ring slot nut driver on one end, regular nut driver on the other. Couple of photos of some of the tools that were sold. They turn up on eBay regularly enough that you should have no problem finding one. or you can make one out of a short wide blade screwdriver by cutting a slot in the middle to clear the stud and engage the slots on either side.
So when changing the points, you take the nut, wire and small wire shield off, then loosen the ring nut, remove the points, install the new points and condenser wire, tighten the ring slot nut, the install the rest of the hardware and coil wire.
