there are many different methods to applying graphics. the easiest way for you to paint the stripe on is basecoat the car as you normally would in the white. when you are done, if it is a plain white go to the next step if its a pearl white then you must spray a coat if intercoat clear (clear basecoat). this keeps the tape from imprinting into the pearl. once all that is done let the basecoat dry for the better part of the day. mask off the area for the stripe. use 3m fineline tape to edge it out, the green or blue is fine then mask the rest of the car up to the tape. spray the black stripe. let dry for a couple hours. remove the masking and clearcoat the whole car. apply enough clear so you can wetsand the edge away and buff it out. a high solids clear is nice for this. when done you dont want to feel that nasty edge of the stripe, it should be completely smooth. you can also skip the wetsand and sand all the panels that have the stripe on it with 600 and reclear.