I’m on a PC, but I think this is not the problem.
I first tought that you had an H9… I’m not sure you have the same menu for the ModFactor since it has different features. I’ve had a look at the modfactor manual and saw that the procedure is explained at page 20. It says somewhere that “you must turn the knob to create the assigment”…
At this point I think you should download the modfactor manual and try with the procedure explained there. This doesn’t require the H9 Control software.