rotate model in Czml

I create Czml with 3d model. I want to rotate my model in each time. How I can?

The rotation of a model (and all other CZML graphics objects) is controlled by the CZML “orientation” property, which is a unit quaternion that rotates a vector expressed in the axes of the model to the Earth fixed axes.

Thx for response.
Can you give me one example?

In document for axes and unitQuaternion don’t have description.

Hi Vahid Sohrabloo

Did you figured out how to solve this? I am stuck in the same situation in my "C" code for a 3D model.