Cool. You might first want to confirm that the device is recognized by Alsa as a midi device.
Run:
amidi -l
That should list all current MIDI devices known to Alsa. If nothing is listed, then you'll need to figure out why.
Once it is showing, the MIDI channel doesn't matter. MOD should be able to learn a MIDI CC coming in on any channel. Know this though, once a pedalboard has a given MIDI CC message mapped to a control, it cannot be mapped to another. So for testing, you might want to start with a super simple pedalboard which you know has no mappings, then try to MIDI learn your CC.
Feel free to post back what you find, and we will try to help you from there.