Nikon D90: Set Picture Control?

My dad bought a Nikon and doesn't know how to use it, so he dumped it with me. I'd like to change the saturation settings, but when I go to Menu>Shooting Menu, the top selection, Set Picture Control, is inaccessible. When I select it, a little error box says "This Option is not Available with Current Settings". What am I supposed to do to set it properly? This goes the same for several other options, including "White Balance" and "Active Lighting". I can't access these either, and some others.

When all else fails, read the instructions.

You can view the D90's manual here if you do not have the physical copy that shipped with the camera: http://www.nikonusa.com/...oprint.pdf