Need help on audio system install.

[Jaegermeister2k]

I went to circuit city,and asked them how much it would cost me to let them install my system in the mustang,i got a head unit,2 amps,4 speakers,and 2 subs,i also got all the neceserry cables,so i asked them and they said i had to bypass the mach460 system,or whatever,and the totall came to $527 that's pathetic,i of course left,so i'm thinking all i gotta do is put my system in the car,it won't have anything to do with the mach 460,i'll take that out completely,that should work shouldn't it?Also does anyone have any diagrams as to how to take the stock speakers head unit and such out?

Thank you for any help.