Try this:-)
1. Start in an upright position with the legs in a staggered stance (one leg about 3 feet in front of the other).
2. If the left foot is in front, put the right arm out in front, and visa-versa.
3. Start the movement by shifting the feet (right foot in front) and the arms. Make sure the front arm goes up in the air and the back arm should be down at the side, slightly behind.
4. Repeat to the other side. Keep repeating in a continuous fashion for a timed period. Make sure to keep the core tight throughout the exercise.