It's difficult to give instructions on how to animate. But these are probably the most important elements you need to have a look at when you learn animation:
Key poses - used to define the most important moments in your animation are vital to understand the action that you are animating. Craft these keyframes carefully e.g. by developing poses with thumbnails.
Extremes or extreme poses like anticipation and overshoot are needed to prepare and catch the animated motion.
Breakdowns - define the middle position between two keyframes. Use this to define the arc that the element will travel on.
This video gives you all the step by step instruction you need to animate a headturn in any animation software. This exercise is a good start to learn character animation.