I am guessing you have cable and have the cable connected directly to your TV.
If so, then (depending on your TV) you should have two connectors on the back of your TV. One of those connectors will be RED, the other WHITE. These are RCA audio connectors. Right under the connectors it should say something like LINE OUT or AUDIO OUT. Those are what you want to connect to the red and white connectors on your Yamaha (to the SAT/Cable input).
You will need a RCA audio cable. If you don't have one, then you may want just a cheap set to get you going from your local Radio Shack. Just a few bucks will get you a pair.
If you have a cable box or DSS receiver, then you should let us know - provide model number! - and you can be walked through on that as well.