Soldering is generally pretty straight forward. You actually don't need any solder for the motherboard end, as the holes all have solder in them. So you just need need to heat it up and slide the wire through. I suggest using at least a 30w iron as a 15w will have trouble getting the lead free solder hot enough. All resistors on the connector are optional, it's just to prevent damage as some ports are 5v and the motherboard is 3.3v.
Here are some bigger pictures
Recently there has been a new way to wire Xenons that is supposed to be better, I have never tried it but I have included the diagram on how to wire it.