Ok Spanner,
Assuming you have the DSS type Regulator / Rectifuer unit.
Starting with the old REGULATOR at the top of your picture & working vertically down...
Disconnect the BLACK wire, and connect it to one of the BLACK/ RED spades of your new unit.
Disconnect the WHITE wire, and connect it to the other BLACK/RED spade of your new unit
Disconnect the GREEN wire, insulate it, and tape it up out of harms way.
Now your old RECTIFIER...
Disconnect it from the bike via the large loom plug, ie 3x YELLOW, RED/WHITE & GREEN
Plug the bike loom connector into your new Reg/Rec unit.
Job's done.
(if for some reason you don't have the loom plug simply connect the YELLOWS together (any order), the GREENS together and the bike RED/WHITE to the new unit RED. Ensure all these connections are soundly insulated & stowed securely.
Simon.