Ashwa means horse. Sanchalana means movement. It is called the equestrian pose.
This step or posture is performed in the same way as the fourth step or posture of this Vinyasa. From Adho Mukha Svanasana raise the left leg and when inhaling take the leg forward and put the left foot between the hands.
Simultaneously put your right knee on the floor, push your hip down and forward as you raise your torso and push your chest forward.
Om Adityaya namaha: Salutation to the son of Aditi, the cosmic mother.