Connecting cable, and a dvd player

Question

Can you tell me the correct setup to conect a cable box and dvd player to work. My husband has tried a few connections and the dvd player does not work. We are running digital cable, we do not have HDTV. Right now we have the cable in to the cable box, then cable to tv and the red, white blue to the back of tv and then to dvd player. Can you tell me if we have it hooked up wrong. Or what connections I need to change.