Quaternions and rotation and MotionFit IMU

ok, so I can read data into my android application but now I have the issue of using it. I am unfamiliar with opengl and rotations so any help is greatly appreciated. What I need to know is:

"how do I use the quaternion to rotate a cube for example representing the orientation of the MPU9150 MotionFit IMU?"

thanks in advance

Mike