 -click
            its path curve.
 -click
            its path curve.
          .
 .
            The Attach to Motion Path Options window appears. See Animate > Motion Paths > Attach to Motion Path.
See Follow.
You have now created an orientation marker. The orientation marker is represented in the view by a small triangle with a number next to it.

 -click
            and drag in the scene view to adjust the side twist of the motion
            path node.
 -click
            and drag in the scene view to adjust the side twist of the motion
            path node.
         
To change the timing of a marker