Step 2: Put your left foot down, and put your knees down vertically as far as possible without bending, as shown below:
Step 3: Put your left foot down and push your right foot backward, as shown below:
Step 4: Make sure these two feet move at the same time, as shown in the following figure:
Step 5, then lift your left foot again and repeat the first step, as shown in the following figure:
Step 6: Put your left foot down again and cycle this group of actions, as shown in the following figure: