I have an XPS file with a model and my question is do I need to do something special to it so I can use it as a armor mod it has a skeleton but the parts are all marked as one do I need to separate them or they can stay like this.

Yes, i need to load on blender ( install this plugin https://github.com/johnzero7/XNALaraMesh) and convert to obj/fbx , then u can use outfistudio to load in to the game, just import the obj/fbx file and copy the bones of any armor/body male of fallout 4 , this tutorial can help u https://www.gunetwork.org/t21004-easy-method-to-port-nv-facemask-to-fallout-4?highlight=Easy
i recommend export the xps in to a obj to avoid uvmap issues