You have to have hardware too. Either a tv tuner card or a capture card and an external tuner (an old vcr works good for that). There are also external usb type tuner/capture devices. These devices will allow you to watch and record tv on your computer. You could also burn to dvd after recording. To output to your tv from the computer, you have to have compatible outputs on your video card.
About how to hook up up a tv, you can use normal analog conections with composite (the yellow rca jack on your vcr or tv or whatever) or s-video for the video, and normal rca cables for the audio (the red and white rca conectors on your tv/vcr or whatever). You generally need an adapter to go from mini plug (most sound cards/onboard sound use these conectors) to rca. The adapters are only a few dollars.
You can also hook it up digitally if you have compatible equipment but I'm not that farmiliar with that.