Hi Johan
You need to understand the Basics of Midi before you connect the 2 boards together; here are some links to get you started. http://www.borg.com/~jglatt/tutr/miditutr.htm http://www.geocities.com/sunsetstrip/studio/5821/midi-basics.html http://www.borg.com/~jglatt/tutr/whatmidi.htm
Either keyboard can be used as the Master, so choose the one you feel most comfortable with.
As a Rule of thumb the default settings are, channel 1 is usually the right hand, and channel 2 is usually the left hand.
Hope this helps.

Bill