Hi joaquin45,
Congratulations on the new Bighorn and welcome to the Heartland Owners Forum.
In addition to the cable TV coax connector in the Universal Docking Center (UDC) you probably have 4 satellite coax connections. The coax wire from the dish gets connected to one of those 4 connections. 2 of them go to the roof for a rooftop Winegard dish, if you were to get that. The other 2 go to living room and bedroom locations. The bedroom connection is probably in the closet. The living room connection is near the TV.
You'll put the receiver near the TV you want to use with satellite.
The cable TV connection will not pass satellite signals between dish and receiver.
If you want to use 1 receiver with 2 TVs, that gets complicated. Like a residence, the normal way to do so is to get a 2nd receiver. But I'm not sure your Tailgater supports more than 1 receiver. If you can split the output of the receiver, you may be able to run the receiver output back into the cable TV coax connector next to where the receiver gets the satellite signal. You may then be able to use the other TV by way of its cable TV connector.
Before trying to set things up with the RV connections and internal wiring, run coax directly from the dish to the receiver. Once you've got it working, you can try out the internal wiring.