v3.0 CNC Shield in K40 help please

[CustomCreations]

I am trying to configure my v3.00 CNC shield to work in my K40 laser as the old board was DOA. I have GRBL 1.1f loaded onto shield and now I am trying to figure out where the connections go and what settings need to be configured for the laser to work and fire. After some reading, I have noticed that the laser fires on a 0v and disables on 5v so I do not know if I have to build another circuit for this or if it can be inverted in GRBL. ANY and all help is greatly appreciated!

TIA!