Dumdfounded

Sup? I don't know much about car stereos let alone the wiring. I got a new stereo system for Christmas. Am trying to install in my 1989 Ford Escort Wagon that has atleast 160,000 miles on it.
My problems are: 1) I have no idea which wires lead to where except for enough to get the stereo to turn on; 2) I turn my headlights on and my stereo shuts off for a second ; 3) there is a clock between my visors and it starts over every time I turn the car off; 4) the memory in my stereo also does not work.
Please HELP! Am very frustrated. Thanks man!