The Switch uses an HDMI cable to communicate with the TV. Connect one end of the HDMI cable into the back of the Switch dock.
Connect the other end of the HDMI cable to an HDMI port on the TV.
You may need to adjust the input on the TV to use the HDMI port you connected the Switch to. If you're not sure which one it is, make sure your Switch is powered on and rotate through the HDMI inputs until you see the Switch interface.
Nintendo is just coming off their high from the Switch update that enables Bluetooth audio devices, and they’re riding that wave.