This is how to check the origin in LightBurn for the stock K40. See the links below for info on custom bed size, and checking orientation and stepper motor wiring.
Go to EDIT > DEVICE SETTINGS and make sure origin is bottom left:
Go to EDIT > SETTINGS and look for output settings (job origin). make sure it is bottom left:
Look at your grid, the green and red boxes should both be lower left (you can still use absolute and/or user origin in the cut settings as usual):
Also see these related articles: