Anthem mrx 310

I purchased the mrx for use as room correction only. I'm having a heck of a time trying to get to the arc. I was able to do the miked measurements but I don't seem to be able to get it to load. I've tried Anthem and they keep telling me that operation of unit starts on pg. 38 of the manual. But it doesn't say how to impliment the arc.

If anyone has any ideas on how to get this thing going pls, let me know. Maybe, I'm the village idiot, but this is really frustrating.
What's the rest of your system?
go to setup menu for the input you are using and make sure arc is chosen for the output