how do i program music in car tutorial

Greetings and salutations, I'm playing with the car in the unity i'm designing stages in 3d max as well as cars i have ready pls using vue 9 in max to bring out the stages for the game but as i play with the tutorial to the car and read over the documents it doesn't descried that in java script how to add ur own music as wel as this i'm a indie music artist so i would like as a test try to program music tracks in the java script i imported the music to the game engine and opened up the java script but don't seem to see where u program the file. and also i got a couple of cars redy for the turt stage as a test run is it u jus import the model and link it to the same specs as the model provided thnax in advance sinsir