Where does the ground wire go?

[Toothless]

Thanks . One of the bulbs is a different size- doesn't even work but I just screwed it in there for the photo.

What is the best way to secure the cords to the top side of the board? I don't want them shifting at all so was planning to secure them to the top of the board, then run them through a tube part way up the chain before they exit the enclosure. This should keep any curious monitor claws away from the wires .