Upcoming marching band audition friday,,, HELPP!!?

Alright, im 14 years old movong on to high school next year. Im going out for marching band, but im struggling with the piece of music that i have to play. Im going out for base drum, but i still have to audition on snare. The piece is called "How the west was won" by Ken Darby and Alfred Newman, its in cut time, and normally i would have help preparing for this, but school is over, i could really use some helpful tips, or links so i could listen to this. Any help given would be awesome, thanks..