Beginner: For the bow, keep elbows tucking into the body and rest your head along the floor. If this posture is hard on your knees, try adding an extra mat or placing your knees on a blanket. Hand placement is important, keep hands even in width with the shoulders to help comfortably distribute the weight of the body.
Advanced: In Sunbird bow, keep the head hovering gently above the floor, building immense strength in the shoulders and arms. Your abdominal muscles are super engaged, super energized. Extend the line of energy from the length of the leg all the way through the foot. Can you lift a little higher?