Take off the points cover

Remove the points plate screws and lift the plate away

Remove the advance/retard mechanism retaining bolt

To remove the advance/retard mechanism from its taper, you will need a suitable puller

You can improvise a slide-hammer puller by using one of the long toolbox cover retaining bolts together with a washer and the heaviest socket you can find

Screw the puller bolt into the end of the advance/retard mechanism and use the slide hammer to shock the mechanism off its taper