FreddB wrote:
On the back of the camera, right side, press the "i" button; bottom row third "button" from the left is the AF-area mode; select single point AF; press the "i" again. Voila!
~On my D5200, I have to hit the info button twice to be able to change settings. I bought this body used with no manual, but all settings can be found online very easily - YouTube is very informative for this series of camera.