How to set-up end stops in Arduino/Grbl

Hi all, I have installed my end stops. What do I have to do to set them up to work properly? I have the black wire connected to the black pin and the green wire connected to the white pin(to match the + & - of X and Y axis on the CNC Shield. I have manual control of the axis’s in both + and - directions in X & Y.

Arduino Uno
Protoneer CNC Shield v3
Markerbot switches

Thanks for the help

The second entry Google found for me gives the answer. Is that so hard? Configuring GRBL

Paul

Here is a link to the new site if anyone needs it. Easy as pie and no unnecessary comments...