In case you cannot see the video, here is a still sequence -
Stand by a low window ledge, a table, or a sofa back. Keep the feet facing forward and a handsbreadth apart.
Slowly bend at the hips. Push out your buttocks as if you were planning to sit, and lower your body until your knees are flexed to 45 degrees. The shoulder, hip and heel should be in a straight line. Hold this position for 10 seconds. Slowly stand up again and repeat 5 times.