Hi
I just had a look, my regulator also 5 wires - 1 x yellow, 2 x blue, 1 x red/blue and 1 x red. I think the metal tab is a ground, this is bolted to frame, bt am not sure.
Yellow is from the stator, so assume this is supply
The two blues on mine go to either terminal on the thermostat
The red/blue and red wires go to the same colour wires on the fan.
I have no other connections, as I removed all the loom for lights, horn etc previously in order to keep things simple when I replaced the regulator.
Hope this helps.
Paul