The antenna should be preconnected to any TVs that came installed with your unit and any cable outlets you see. You should also see a cable outlet on the driver’s side of the rig (by all the other hookups) That is cable INPUT for when the campground has cable tv at your site - for that you should run a coax cable from the rig to the cable connection usually by the power pole.
To use the boomerang antennae, find the tv panel in the rig (on the side of the cabinet over the sink in our units) - it has a 12v outlet, a cable outlet, a small led light and a button. That button controls the signal booster for that boomerang, over-the-air (OTA) antenna. Push the button and turn the light on when you want/need to use the OTA signals, push the button and turn the light off to use cable. If you’re using OTA you can then turn the antenna using th crank or nob in the ceiling to “dial in” the channels.