How to do Ardha Baddha Padmottanasana

1. Stand with your feet together 
2. Inhale, draw the right knee up and slightly out to the side, grasping the ankle or shin with both hands 
3. Taking hold of the shin or ankle with both hands and drawing the right foot up to the level of your left hipbone 
4. Pull the right heel in toward the belly with the left hand, place the ankle on the upper thigh 
5. Reach your right hand behind you to grasp your right foot 
6. Inhale again, lift the left arm overhead 
7. Exhale, bend forward 
8. If possible, place the left palm on the floor, fingertips in line with the tips of your toes 
9. Without forcing, draw your chin toward your shin 
10. Take 5 to 10 breaths  

To Release 
1. Inhale while looking up and lifting your chest. Exhale here.   
2. Inhale, press firmly down through your standing leg and draw your torso back up to vertical (Bending the standing leg a bit can make this easier) 
3. Release the lifted leg to the floor  

As you do this Asana you will feel your hips and shoulders open. You will begin to feel your core engaged and strengthening. This pose also helps to clean out your organs and increase the flow in your circulatory system.

*Repeat on the Other Side  
Source : http://www.yogajournal.com/practice/1246