Pull left knee in toward chest (A), then extend left leg straight back behind you as you extend right leg forward (B). (health.com)
Reverse motion; as you return to start, bend left knee, lifting left foot behind right leg so that your right hand and left sole touch. (health.com)
The natural movement of the body in the crawl is right hand forward with left knee following, then left hand forward and right knee following. (mindbodygreen.com)