Let me see if I can give you the instruction you need. Let me say in advance, it's doubtful you will be able to do this on your own. But if I explain it to you, it will at least give you a proper understanding instead of just feeling like you are overpaying for something you feel you don't need.
First, the pots you are speaking of rarely fail. What happens is the actuator fails but picks it up through these hall effect passive sensors. So you will get symptoms of failed pots, but it's actually an actuator issue.
Secondly, I think there are a few things here beyond your scope. First, there is a process of actuator centering where you toggle the scan tool, and use an attachment to the front of the actuator to adjust the armature to make sure it's perfectly centered. That's the metal block I think you've seen, though I didn't check the hyper-link. Along with this is the actual actuator bleeding, where you open the three bleed screws on the actuator in order to toggle the bleed sequence on the scan tool, thus, bleeding all of the air out of the actuator itself. There is also a separate bleed you do anytime you open the hydraulic system up to bleed the rest of the system out.
Finally, if you complete all of the above, again you'd need a scan tool and technical knowledge to do so, you need to perform self learn after the (new/like new/used) actuator has been re-installed. If it isn't run the new actuator still won't work. It would take an even longer post as to what "Self-learn" actually does. There's a very specific reason it's run, and it collects very specific data points that stores in the tcu itself.
Anyway, I hope this helps. Yes you can replace the actuator yourself, but you still need to have it bled out, and self-learned afterwards even if you don't do the recentering process.