[HELP] Adding a texture to a vehicle

Hi There,
I’m trying to edit the texture of a vehicle that I found on the internet. But he doesn’t have a paintjob. How do I add a paintjob to a vehicle that I don’t own?
Sorry for the english errors, I’m using google translator.

Any help is welcome, thanks!

check if the texture is in the .ytd file (use openiv) or check if in the tunable files it has a livery .yft (use texture toolkit) if its not then you need to ask the author to add the texture for you, or you need to edit the car .yft (use zmodeler 3) if the author let you do it