If your soundbar does have an HDMI ARC input then you would have to turn this function on in the TV & Vizio set up menus. Most sound bars do not have ARC. Home theater in a box systems that have a disc player in them sometimes do.
Your Sharp TV probably has an optical audio output that you can connect to the sound bar. This is not controlled but the volume control of the TV so you just turn the TV volume all the way down. Select the optical input on the Vizio and use its' remote for volume.