So you have several questions here.
Sensorless Homing:
First, if this is based on your previous question I was describing “manual” homing. Sensorless homing is something completely different. Since you have TMC stepper drivers, it is theoretically possible. If you really want sensorless homing, I’d pull that out as a separate question.
Error on the screen
I don’t know what that error is, but I’d start by sending M221 g-code to get a report on the state of your drivers. In addition, it would be helpful to understand what firmware you are running…one maintained by V1, or did configure it yourself. Perhaps @jeffeb3 has some insight on this error.
Where to get updates
V1 releases it firmware on this page.
How to home
If you are running V1 firmware, press the knob, select the V1 Custom menu, and you will find a menu item for Homing X&Y. It can also be triggered using G28 g-code. How you send this code will depend on your setup. Worse case, you can put it on an SD card and run it like any other file.
Milling Operation Programs
There is a software pipeline for producing things with the MPCNC. Two references:
Personally I use Fusion 360 and and SD card, though I have a pendant to make manipulation of the machine easier.