Sounds like a really old analog tv. That is an F connector that you connect an antenna to.
If the set has no other inputs you use an F- male to male cable and connect it to the cable boxes ch 3-4 rf out and set the tv to either ch 3 or 4
That's the lowest quality.- most cable boxes still have RF outs,
Verify the tv doesn't have a/v inputs or hdmi input...
How old is it?