HELP! Understanding MIDI

[Thomas Fisher]

The equipment is:
  -Edirol UM-1 ex   USB
  -Kawai KC-10 keyboard

The software is:
 -Jack
 -Rosegarden
 -Patchage
 -ZynaddSubfx

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HELP!
  I am stumbling through this midi hookup, which is becoming frustratingly 
obvious to me that I am not comprehending a something about this MIDI hookup. 
I know that it can work in that I accidentally had it all working, once, but 
can't get it working again.  The deeper I get into some of the guides, the 
more lost I become.
Anyone with a straightforward suggestion?
 
 Thanks
Tom