How do you make instrumental's

No remove the vocals or make them softer. I read this article and tried to follow it

"You need to go into the track details. I don't have GB in front of me so i'm unsure now as to what the effect is called, you'll have to experiment: but you have to run the song track in dual mono, (copy the existing track onto another track) so you have two tracks of the song. In the track details, you will be able to phase shift each of the tracks so they are phased opposite (make sure its not a modulating phase shift). if the original song was mixed down with dual mono, you will be able to cancel out the vocal line. if it was recorded in true stereo, the vocals will be weak but still there.
That is essentially what the expensive voice removal software does.
so, yes, it can be done on garage band
good luck"

So i created another track and copied the song to it, and now i am lost

Hey thanks. I tried Audacity and it worked, until i saved it as a wav and when i listened to it in itunes it was converted back to original. So yea, that guy had no idea what he was talking about. I just love how my voice fits this song. Oh well, guess i will have to find another song. Thanks for the help. i love that website. thank you so much