96 mazda e2000 audio wiring?

I need to know what the different coloured wires from behind the original stereo represent - especially the brown one. i recently installed a new stereo - should have been as simple as abc, but it hasn't worked and the fuse to the dash and tail lights is now constantly blowing - please help. the stereo does have power, however it doesn't seem to transfer through to the detachtable face plate. a simple comprehensive explanation of the wires should solve all my problems.

thanks