I answered which wires are what. As far as soldering two different size wires together, it's no different than soldering two of the same size wires together, with the exception that is will not take as long to heat up the smaller wire as it will the larger wire. slide the heat shrink on, strip the wire, slide the strands of the smaller wire in to the strands of the larger wire so they're interlaced, place soldering iron underneath copper, insert solder from above, let it flow over the copper, remove soldering iron, let solder harden, slide heath shrink over solder joint, and apply heat to seal. ta-dahhhhhhh