Can anyone help me figure out how to install the ignition wire for a stereo in a...

[socceryes2003]

...01 chevy cavalier? I want to install a aftermarket stereo...but i don't know where the ignition wire or accessory wire are located my wires...i've been told that i have to run a wire from the ignition but i don't know how to run such a wire...can u help me??