New TV Converter Boxes

Question

Hi...I have older relatives with old tv's (25 years) that are not "cable-ready" tv's. I picked up a Zenith converter box for this new transition next year. The only thing on the back of the tv are the 4 (2/UHF-2/VHF) s***w terminals for the antenna. I was told to get an adapter from Radio Shack, which I did, so I can now connect the antenna. Where do I connect the RF Cable to the tv?? There are no other connections on the tv at all, being an old tv. Thanks for your help!!!!!