Hi deputysteve,
Welcome to the Heartland Owners Forum. There's lots of useful information here along with a great bunch of friendly and helpful people.
While this can vary by model and floor plan, there's usually a set of coax connections in the Universal Docking Center (UDC) where cable TV and satellite connections are made. The cable TV connection and the rooftop antenna come together at a signal booster which is usually located in the bedroom. Look for it in the bedroom closet or in a cabinet.
The signal booster must be ON for over-the-air TV and OFF for cable TV. The bedroom probably has 2 wall plates at the signal booster, with a jumper connecting them. That jumper routes either cable/antenna or satellite to the bedroom TV.
In the living room, there'll be a coax wall plate with 2 connectors; one for satellite and the other for cable/antenna.