Installing an amp in a 1996 Mercury Sable

Look at this amp kit from streetwires to connect everything: http://www.crutchfield.com/S-DUoNxWkFsiU/cgi-bin/ProdView.asp?s=0&c=11&g=711&I=211PS8RI&o=m&a=0&cc=01&avf=N You will need an LOC also which takes a speaker level signal(it ties into a set of your speaker leads to get its signal) and turns it into a preamp output for your amp. Dont connect power to the harness under your dash. You need to go directly to your battery post with the + power cable and the ground cable needs to be grounded no more then 3 feet away from the amp on clean metal. If you need more details ask.

Thanks customsuburd, he gave me most of those wires, I think I need the LOC(is it the same as the speaker level to line level converter ?)  How do I tie that into my speaker leads? Is that where the harness under the dash comes into play?  I really want to understand this stuff.