why are there 2 boxes in the texture ?
What do you mean? Are you referring to the darker squares in the material thumbnail at the top? Vray materials tend to look that way in SketchUp’s Materials panel.
By the way, please correct your forum profile. SketchUp for Schools is a web based version for school children. It doesn’t have a Materials editor like you show and doesn’t have access to Vray. What operating system? 2023 is not an operating system. From your screenshot it is clear you are using either Windows 10 or Windows 11.
You use Binding in V-Ray.