What I want to do is setup the camera in MANUAL MODE. When I take the picture, I want it displayed on the LCD along with the black and white HISTOGRAM(not RGB). I then want to adjust both the shutter speed and the f stop on that same screen . I know I can go to the OVERVIEW and that will display the histogram, where I can adjust the shutter speed and f stop, but then I have to take another picture to see the results. I am quite sure it can be done. I think I had it one time, but forgot how I did it. In other words, take a picture, see the image on the display with the histogram, adjust with the command dial.
If you want to use the histogram to change your aperture and or shutter speed to tweak an exposure you must change the settings and capture anther image. If you want to modify the image that you just captured in camera you must use the Retouch menu. See pages 174-189 in the D5000 Users Manual. You can also use Live View but there won't be a histogram displayed. See pages 41-46 in the D5000 Users Manual. Good Luck and Enjoy your Nikons!