Hi,
the old unit that you are showing in the first pic is just a rectifier without the regulator.
The new unit is a combined rectifier/regulator.
The wires on this new unit mean the following:
Yellow (three wires) - alternator AC output, order of connection to the main wire harness is unimportant
Red - +12V from rectifier to battery
Green - Ground from rectifier to frame or battery or main wire harness
Black - +12V from ignition, provides power to the regulator
White - +12V regulated to alternator field coil
You'll find the counterparts to the black and white wires on a different connector in your alternator's wire harness.
Here's what I would do:
Identify your old regulator. It has a rectangular metal cap with rounded edges on it. Unscrew it and find that three wires are attached to it's back with individual female flat connectors: Black, white and green
Take the black and white pins out of your new unit's connector and connect them to the flat connectors that you have identified in the previous step. Insulate them with shrink tube or crimp insulated flat connectors on them.
Cut the ring and crimp a male flat connector on the green wire of your new unit. Connect it to the green wire that you took off the old unit.
Re-arrange the remaining wires in the new unit's connector so that they match the 6 pin connector in the main harness. The yellow wires all mean the same, so you don't have to care about their order.
In order to get the pins out of the new unit's connector, you could use a tiny flat head screw driver to "unhook" them, or cut a thin piece of sheet metal to make a tool that just fits into the groove that you see in the middle of each slot. Try it on the old rectifier first. You'll see how the pins are hooked into the connector housing.
Judging from your last pic, I guess that you've bought a new unit, because you have charging issues. Did you hook up the battery the wrong way and fried your regulator? Did you test it and found that it's dead?
If this is not the case, your troubles just seem to be caused by a bad/dirty/oxidized +12V pin (red) in your rectifier's connection to the main harness. Your new rectifier will not work better than your old one if you do not clean this pin or change the whole connector. I had the same problem: The connection was bad, resulting in increased resistance which caused a lot of heat melting the connector. The damage looked exactly the same. After cleaning this connector, my charging issues were gone.
I hope my "Denglish" explanation make any sense to you.
Cheers
Carsten