The Fisher 100-R Tuner and MPX -100 adapter ??????

The 100-r tuner has a & b channels but are they both in mono? I have a MPX -100 adapter that is marked L & R . Can anyone explain how to hook this up properly and what are the two unparked pots on the back of the mpx ? the front ones are marked level . and What in the world is the FM-AM setting on the tuner . It seem fm comes out of the left channel and am comes out of the right channel ? BTW this is a good sounding tuner with a cat eye scope type indicator that can be bought pretty cheap on the web! Thanks !