Blender and pre-existing models/skins from other games

[TheHusseler]

I got a hold of some saber parts from Jedi Fallen Order, they come as .obj files and .tga textures. The models are unwrapped as far as I can tell in Blender (i'm fairly novice at it), so what I thought I could do was crack open the .glm of a different saber, drop in the parts from Fallen Order I want arranged however and then apply the textures. But I cannot for the life of me get the textures to apply to this model, I'm going insane and google results only pull up unrelated answers.

Does anybody have good suggestions or tutorials on how to do this kind of specific thing? Feels like it should be easy.