Alright, to cut straight to my problem, I extracted the .b3d model for SCP-173 in Blender and edited it a bit, and gave it a custom texture too. When I replaced SCP-173's original in-game model and texture with my version, in-game SCP-173 had my edited mesh, but the texture was just gray. I am really not sure what to do to fix this problem, if anyone can help, that would be greatly appreciated, thanks for reading.

You have to apply the textures in fragmotion watch this vid it shows how to apply textures