-There are various 3d model types but you can only import/merge .OBJ formate 3d models for porting. So first step is to have some model samples from deviant art and some other 3d model sites by following:
But to convert model from other formates, most likely XPS, you need XNALara XPS
By XNALara XPS, change character pose and height according to 3d Max Skeleton or in other words match XNALara XPS Skeleton same as 3d Max Skeleton, for example, select palm or hand of character in XNALara XPS and give it same X axis, Y axis and Z axis values as in 3d Max, does same to all bones in XNALara XPS, by that you don't have to rig it in 3d Max and your exported model from XNALara will accurately skin on 3d Max Skeleton due to same pose as of 3d Max Skeleton and you can save hours of moving and placing mesh in 3d Max, where you just need to fix minor mesh issues according to provided video.
-After conversion open provided sample file and import/merge converted or downloaded model (open the file with in folder of "Without Mesh).
-Now follow following Video and Pictures for rigging character, adjust skeleton over object while if your object is in multiple parts you can combine it in to one by attaching, while you can also import in single mesh but I recommend to import in multiple part so you can delete unwanted parts on character, where also make sure that maximum skin covers the skeleton, adjust it in that way, so you don't have to make much adjustment after rigging (but make sure don't change any pre-set properties of sample file, as I set it with fixes in it):
3th Step (Optional):
-Fix for opacity of objects:
some object or models have opacity issues mostly happens with hairs, so find that hair related material file in skin directory to follow following method:
To fix it, just port them as they look in picture, while change values with in files to fix it and also delete and replace texture files from model source folder (where .OBJ file is) to EXPORTED model/skin folder (where skin.ply file is):