Sounds like you have a "Super dish".. I won't bother to explain save to say one of the coax connectors is for a 2nd dish (it is an input)
You should need only one coax. either of the other two ports.
To set up.. Go to antenna set up (I forget the path, Menu 311 is what my DTV converter uses but I think it was different (611?) for Sat receivers)
Enter the zip code where you are parked and write down the 3 numbers it gives you back (Azimuth, Elevation, Skew)
Pre-set Skew and Elevation.
Swing slowly through the azimuth while watching a portable TV hooked to the receiver.
When Signal peaks, Touch up Elevation and then Azimuth (They interact) SKEW is usually good.
Make sure the post is straight up and down (Plumb)
Should do it..
The software in that receiver for aiming the antenna is comparaible to the best professional sat finder meters (Bird Dog) which sell used for over 1,000 dollars.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times