with that code above you are dumping a group or whatever fbxloader returns into a mesh (primitive puts an existing object into the tree, that’s why you see the model). in threejs a mesh needs to have a geometry and a (or multiple) materials.
im guessing something like
as for these two textures, don’t expect the first one to be interpreted as a normalmap if that’s your intention. i wonder why at all would you want two materials like that.
do you know how your problem is solved in just plain threejs?
and start slowly with simple stuff, otherwise everything will turn into a guessing game. all i can say is that the way you’re handling it is neither how meshes work in three, nor materials nor how normalmaps are applied. i would suggest you spend more time on threejs fundamentals first.