The TV in your living room should already be connected to the Polk. The back of the TV should have an RCA cable (the red and white) connected to TV Out. This is connected to the Polk on one of the inputs. All you need to do is turn on the TV and the Polk, make sure you have something with audio playing through the TV then select the different sources on the Polk until you hear something. I cannot remember which source it is on - could be AUX or CD1.
If you do not get anything you may need to turn on the option in the TV sound settings to turn on external speakers.