You have two speakons for each amp in dual mono mode. That means you can hook up your cab to either speakon of the left or right amp in dual mono. If you hook up to the right side amp make sure (#5) right level is full CW (to the right).
I would be more likely to use the left outputs, if you find you need more headroom all you would do is power down, place the rear switch to bridged and power back on (now 1080 watts rms). If you want to run in bridged would also have to switch your cab from the right channel to the left channel (do NOT use the right outputs in bridged mode). Both power amps are feed the same signal, they are not independent "channels".
Start experimenting with the "recommended settings" in the manual to get acquainted with what all those wonderful controls do.
Just call me B-String 2
GK Club #488 Big Cabs #175 Peavey Amps #92 50+ Club #44