Rhodes Chroma Polaris

I just had a question that I'm sure is simple.
 
I'm wondering how to use all 6 extra midi channels, and assign
different patches to midi different channels.

The closest I've gotten to this was using the "link lower" function,
assigning a bassline patch to midi channel 2, and a string patch to
midi channel 3, being controlled from an external sequencer.
 
I'm trying to figure out how to do the same thing, but by using all 6
midi channels.
 
I have the manual, and have read it, but it didn't quite explain it
clearly, and the print on that particular page was very hard to read
(got it online).
 
If you could give me some simple instructions to the secrets of
unlocking the 6 midi channels on the polaris, and how to assign
different patches to different channels, it'd be much appreciated. 
 
thanks!