Auto Selection of AF on 1DX

With the 1D X, you can choose to have the camera select the starting AF point automatically, or you can choose to have the camera pass the active AF point around the 61-point array automatically -- but you can't have both at the same time.

• In One Shot mode, Auto AF Point Selection will cause the camera to choose the active AF point automatically from any of the 61 points in the AF array. It will choose the AF point covering the nearest subject. Once AF is achieved, AF distance is locked and the AF point is no longer active; the inactive AF point will not be passed around the 61-point array.
  

• In AI Servo mode, you must always select a starting AF point. If you've chosen Auto AF Point Selection, the camera will pass the active AF point around the 61-point array as needed if the subject moves off the manually-selected starting point. The starting point need not be the central point; it can be any point in the 61-point array. However, you must choose the starting point -- there is no option to have the camera select the starting AF point automatically then pass that AF point around the 61-point array automatically.

These two modes are explained starting at 02:20 in the first video tutorial in the link you provided.