I am trying to install a lighting fixture that I bought from Ikea. The ceiling box has one black, one white, one blue, and one yellow lines (as in the photo below). But, I cannot find a ground line in the box. Can anyone explain how I can connect the ground line in the lighting fixture? Also, I would like to use a switch to turn on and off the lighting, but I'm not sure which hot wire I should use. I guess it may be blue or yellow.