If both mystery model # TV and soundbar Both support HDMI-ARC then the owners manuals will tell you how to turn ARC on in the TV menu and select it as the input of the soundbar.
If they don't both support ARC then you will have to use whatever audio output the TV has and whatever input the soundbar has. If they don't have matching out-in types then you would need an active converter.
This is the kind of answer you get if you can't go to the trouble to give us enough information to give you a proper answer.