The 12V system is quite a bit simpler than the Wipac system, as there's no longer a need to switch the alternator output with the headlight. It's probably easier to refer to the differences in the wiring diagram pictures to see what needs to be removed...

The traditional conversion uses a single phase (two wire) regulator by joining the orange & light green wires. My diagram shows a 3-phase (three wire) regulator connected to the three alternator wires, which will also work just fine.

Disconnect and remove the 6V battery. Note the brown wire that went to the negative terminal; we'll be connecting the 12V battery positive terminal to it later (via a 10A fuse).

Disconnect and remove the rectifier, noting the brown wire that went to the rectifier negative terminal (you'll be connecting the 12V regulator to this wire later...)

Remove the orange, light green and white wires, as well as the resistance wire, from the main loom

Remove the 6V ignition coil

Remove the headlamp bulb, sidelight bulb, stop/tail bulb (and any other 6V bulbs)