It’d be easier to set up this in H9 Control, but I haven’t tried that myself.  And you did say ‘… in my ModFactor’.  We are stretching the limits of my memory bank here, but I think I’ve covered everything you’ll need (below).

• Press the encoder and right Footswitch at the same time to enter [System Mode].
• Turn the encoder until you see [MIDI], then press it.
• Set the [RCV CH] to the same MIDI Channel your MIDI controller is sending on.
• Your controller should be sending CC value 127 on switch press, and CC value 0 on switch release.
• That value can be from any CC Number 0 to 99, or MIDI pitch bend [BND].
• Reserve one CC number for preset UP, and a second CC number for preset DOWN

• Turn the encoder to [RCV CTL] and click it.
• You should see the pointer flashing toward left part of the display.
• In this mode, the left / right footswitches each control one half of the display.

• Turn the encoder until you see BK+ on the left side.
• Press the right footswitch. Turn the encoder to one of your CC Numbers ‘reserved’ earlier.
• -OR- press the right footswitch a second time. It will be in [LEARN] mode.
• Send the CC message (reserved for BK+) from your MIDI controller to the ModFactor.

• Press the left footswitch.
• Turn the encoder until you see BK- on the left side.
• Press the right footswitch. Turn the encoder to one of your CC Numbers ‘reserved’ earlier.
• -OR- press the right footswitch a second time. It will be in [LEARN] mode.
• Send the CC message (reserved for BK-) from your MIDI controller to the ModFactor.

• Press the middle footswitch to back up to [MIDI] level.
• Turn the encoder to [OUTPUT] and click the encoder.
• On the safe side, select [THRU] as your MIDI [OUTPUT].
• Exit [System Mode]: Press the encoder and right Footswitch at the same time.