Usually there's a B.O.M.B. (Box of many buttons) inside the entertainment center cabinet. The cable on the outside connection would generally go to that. As would the roof top antenna. With many current satellite systems, they don't want a satellite signal to just go to multiple TVs without paying rental on their receivers. So satellite doesn't usually go through the B.O.M.B.
Now days, HDMI has taken root as the best feed to multiple TVs so the B.O.M.B. might be an HDMI switch. So you could have all sorts of adapters or amps that output HDMI signals coming from the various feeds going to the B.O.M.B.
And then it gets complicated.
So really, what you need is the original Users Guide that came with your entertainment system to figure it out. OR...someone with your exact model will be by and let you know what they did.