CONTROL WHEEL MODE
Most midi keyboards come with two control wheels left of the keys. This mode simulates that as well as two other assignable controls (note that mod is ctl 1 so you probably want the other 2 to be different).
-PITCH
This slider moves with touches on the far left side of your touchpad and (usually) bends the note up or down a whole step through its full range.
-MOD
This slider moves with touches on the middle left of the touchpad and (usually) controls the amount of pitch modulation of a synthesizer (the vibrato). This is midi control 1.
-CTL1
This assignable slider moves with touches on the middle right of the touchpad and can be assigned to control whatever midi parameter you like (I recommend make sure it doesn't overlap with MOD or CTL2).
The number box to the right assigns the control number (0-127).
-CTL2
This assignable slider moves with touches on the far right side of the touchpad and can be assigned to control whatever midi parameter you like (I recommend make sure it doesn't overlap with MOD or CTL1).
The number box to the right assigns the control number (0-127).
-Rel
This checkbox selects between absolute and relative position control. Relative control is to avoid jumps in the control movement. It is very difficult to touch the pad exactly where you left off, so this will make wherever you touch next start moving the control from where it is. Note that when not in Relative mode (absolute is default) you can get some fun effects by deliberately causing control parameter jumps.
-Spring
These checkboxes are each associated with the control wheel above it. It will set the control back to zero when the touchpad is released.