Sorry for my slow reply. I was out of town on vacation. Yes, you have a correct understanding of the situation. Your TV has a Toslink female connector on it. You'll connect a male to male Toslink cable to connect the Monoprice converter to your TV. Then you'll connect the stereo female to dual RCA male cable to the Monoprice converter.
Locate the optical output located at the back of your TV. Put the cable in it. Put the other end of the cable to the soundbar which is labeled as digital audio input. Turn on the power on the soundbar. Set the input via HDMI using your TV. Refer to the user manual provided to you by the manufacturer.