4 channel hook up

i just bought a sony 4 channel amp and on my deck i on't have a sub rca outlet and i was wondering can i use it for font rca on the deck and anyway i can hook up the rear to my sub...i got a high level input connection plug with my song amp nd i was wonder if i connect my deck specker to that will i still have to run rcas ...i have never hooked up a 4 channel amp before!

most 4 channel amps have a built in crossover, you can use the front 2 channels for your front speakers and the rear 2 channels for you sub(s), and you will usually only have to run 1 RCA pair to the amp.