Plug the power cords of both the Comcast cable box and your television into the wall socket. Locate the coaxial cable running from the wall and plug it into the "IN" outlet on the Comcast cable box.
Insert the audio/video, or AV, cables into the Comcast cable box's AV output ports into your television's input jacks. These cables will be colored red, white and yellow. Place the colored tips in the appropriate colored ports on both the cable box and television.
Power up the Comcast cable box and the television. You will need to run a setup of the screen to properly have the cable channels appear.