Your Polk Sound bar is able to accept audio from at least two hardwired sources (Depending on model).
The simplest approach is to connect your source devices (Blu-ray player, DVD player or Cable/satellite box) directly to your TV and the Optical audio output from your TV to the Optical input on the back of the Sound bar. This connection will provide the highest quality audio regardless of whether you are watching TV or DVD.
If your TV does not have an Optical output, you can use the Optical output from your DVD player or your Cable/Satellite box to connect directly to the Optical input on the bar.
With many newer TV's you can use a single HMDI (ARC) connection to connect the bar to the TV. The HDMI port will be labeled HDMI (ARC) on the back of the TV and bar.
It will not function if installed if connected into an HDMI input.