- Edited
mtcat I have tried to put textures in a lot of ways.
It might be a very good idea to post screenshots of the problem or, even better, a project with textures, to make it clear what and how you tried to do.
Have you studied Standard Material 3D and ORM Material 3D?
From the description, it looks like a scale mismatch.
The most reliable way is to texture the model in an external editor (Blender, for example).