Are you a new HD sub, or is this replacing something else? Without knowing what is already installed or not installed, its tough to give any suggestions. One thing that is universal is...
#1) Make sure you have the cables you want to use. The 622 doesn't come with anything for HD. I needed to buy a HDMI>DVI adapter since my TV has DVI inputs and my 811 (which the 622 replaced) has DVI out. My install tech said that they are to supply the component cables if the customer doesn't have anything that works, but I'm not sure if every install tech will have them.
It just sucks to have a piece of new gear without being able to use it, isn't it!