Setting up rigid tapping isn’t hard per se, but finding the right set of instructions was more difficult than I expected. ITSCNC and FadalCNC both have a ton of Fadal manuals and technical instructions, if you’re ever looking for info on your machine. For rigid tapping, ITSCNC has two helpful manuals: rigid tapping installation guide, and spindle drive installation guide.
The rigid tapping guide is not necessarily that useful if you already get the Fadal control scheme, as there really aren’t that many cables involved in setting up the whole system. But the settings changes in the spindle drive installation guide are really, really helpful (some more obvious than others). The big one is that your spindle will not run at all unless you change the control signal the inverter expects from 0-10V to +0-10V. The rigid tapping EEPROMs open both the forward and reverse relays, and use the full range signal to get faster spindle reversal (I assume, anyway). There are a bunch of other drive parameter changes described in the installation guide to get it working 100%.