Music question, and i hope no one thinks i'm dumb. lol =]?

"16 bars" means 16 measures. I ume you know what a measure is, but in case you don't... a measure is the distance between two bar lines (the vertical lines that separate groups of notes within the music). To get your 16 bars, start at where the vocal music (not the piano accompaniment) ends and count backwards. You could also start at the "chorus" or "refrain" of a song and count 16 bars from there. My suggestion is to take the music you want to sing and show it to a friend who plays piano. They can help you find the best 16 bars that will show off your voice. Good luck on your auditions :-)