You mean from Mach3 to UCCNC? To be honest, I'd just go at it. All port mappings will be peculiar to your build, your new power environment will change your motor characteristics, and you'll be selecting different stepper driver settings. Basically not a lot to read across.

My own experience going from Mach3 to UCCNC is UCCNC is very straight-forward - though remember to apply/save settings (it's the one area of the UI that does trip me up over and again). You might want to review your CAM post-processor - I think the G28 you get in Mach3 posts tends to behave differently on UCCNC (though maybe that's just my set-up).

I wouldn't sweat it. Get a couple of mugs of tea on the boil and a pack of hobnobs. It'll come good.