FH5 painting porblems

noobish question, im kinda new to painting in fh5. i started to paint some and and when i tried to apply vinyls the vinyls goes through the whole side of the car. like i tried to add some painting to one of the small flips on the side but then it paints the whole thing through. was wondering if there is any workaround for that?

like for example lets say i wanted to paint this part it paints it onto the back side to and the car not only that piece if that makes more sense

You can’t fix that.