Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
I think that, after hooking up the cable to the TV's cable Input port, you need to go to the TV's MENU
(using either the Menu button on the TV itself, or the MENU Button on the TV's remote), then go to
and select the Cable/Antenna or similar option.
That way, you ought to be able to then, still using the MENU system, to go to Scan For Channels, and get all the channels available tuned in on your new TV.
Does that work for you? if not, or if so, please let me know - so that I can either give you more help until the problem is solved, or else close this case. Thanks.