Audio Systems: Installing Speakers, rear parcel shelf, nissan maxima


Question
I have a '91 Nissan Maxima and a friend of mine and I are trying to install the speakers in the car without going to a place where it's going to cost tons of cash. So i'm trying to find information online to figure out how to just begin figuring out how to install. If you know of a good website or can direct me to a manual somewhere. I'm pretty good on installing things, i just need to have the instructions and such. Any suggestions?

Answer
Omar, Hi.
Loadsa information missing here for me to help.

Speakers, what size and where do you want to place them?
What head unit / amps are involved?
Are you looking to just replace the EOM speakers like for like or upsize?
Are you re-wiring or using the factory cables?
Installing speakers is a piece of cake if you are just fitting 4" into a 4" fitting already in the car as most cars have the wires inplace at the rear, (parcel shelf, doors or rear quarters) to upgrade from two front only to all four.
Need chapter and verse Omar, as I cannot see what you see I need to be told everything as if I was a blind person.
O.K. Peter