You use the Mod editor... which is in the game's main menu. You basically just open the mod in it and save it. It's then updated. At least, that was what I seen someone else talking about. Haven't tried it personally and there maybe a step or two I'm missing here... not sure. Play with it a bit and see if you can get it to work. I also seen them say that not all mods will work like this... something about if the mod changes certain things.. it may not work. But, maybe this'll get you in the right direction. Good luck.