1. Begin lying prone (on the belly). Place your palms under the shoulders with elbows tucking in close to the torso. Lengthen legs with the top of the feet pressing down into the mat.
2. Activate thigh muscles as you press your pubic bone downwards. Image your tall bone tucking under as your abdomen lightly contracts and supports the spine. 
3. As you inhale, slowly press into the hands to lengthen the arms sending the chest lightly forward and up. Continue to draw the tallbone under as the pubic bone moves towards the navel. Use the pelvic tilt to maintain openness in the lower spine as you arch. Only rise to the point where the pubic bone remains on the ground and no pressure is felt in the lower back.
4. Pull shoulder blades back and down without being hard in the back muscles. Tuck elbows in close to the ribcage keeping elbows slightly bent. Encourage the back muscles to work and not just the amrs. Lift eyes and chin keeping comfortable space through the back of the neck.
5. Hold the pose for 10-30 seconds breathing with ease. Complete with one last inhale and then slowly exhale bringing head and chest down and forward. Feel a final elongation of the spine at the end by pulling the torso forward with your hands. Inhale and lift up to your hands and knees. Exhale and rest back into Childs Pose

Remember:

1. Fingers of the hands must remain together.
2. Do not give jerk to raise your body.
3. Navel or lower part of the navel must not ne raised.
4. Put minimum weight on hands. Divideweight on spine and arms.
5. While in final position, the thumb should touch the chest near armpit.
6. In the beginning weight can remain on hands.
7. While coming back some persons bend their head first but it should be avoided. The part of the body which leaves the ground first will return to the ground last.

1. This effects the muscles of the body. 
2. As Swami Kuvalayanandaji has said, "It is beneficial in flatulence after meals. 
3. It is more effective for Asthma, Dyspepsia and Vata diseases and helps in keeping the spine flexible.

Caution:

People having hernia should not perform this asana.