Pictures of the back of your Teac show that there is no optical input.
The adapter you need is an optical digital to analog converter like this one https/www.amazon.com/Digital-Optical-Analog-audio-converter/dp/B004C4WPXA
Connect it to the Aux input on the Teac.
The optical audio output is not controlled by the TV volume control so if there is no menu option to turn the TV speakers off just turn the volume down.
You may have to turn the optical output on, the TV speakers off, and change the audio output type in the TV menus.