Ender 3 Pro, newly installed 4.2.7 main board, newly installed bltouch from creality. Running the Ender-3 Pro- 4.2.7-Marlin2.0.1 - V1.1.2 - BLTouch - TMC2225.bin firmware - the one for no adapter board.

I can't get the Z offset set. The included instructions are vague at best, and I can't find any videos or other guides on how to do it.

What I think i'm supposed to do - run Auto Home. Then go into Control>Bed Leveling>Probe Z Offset and then adjust that so it's a paper's width away from the print surface. Adjusting that setting works to move the print head up or dawn, and I can get it fairly close to the print surface, but at-9.900 it stops moving or incrementing further, and it's not all the way down where it needs to be.

It all seems to be working correctly otherwise - if I start a print it will do the bed leveling routine and then start printing, although it's up in the air when it does, so needs to be aborted.

Any ideas?