Urdhva Padmasana (Upward Facing Lotus Posture) is a challenging inverted posture and an extension of Sarvangasana (Shoulderstand). Proficiency in Padmasana should be gained before attempting this pose.
To enter Urdhva Padmasana, begin in Sarvangasana with both legs straight and the hands supporting the back. Bend the left leg away from the body by extending at the hip, then fold the right leg into place. Take one hand away from the back to assist, if necessary. Once the right leg is in position, bring the left leg into lotus, switching hands if necessary to work the legs into a secure and comfortable lotus.
Once the legs are in lotus, flex at the hip to bring the thigh bones parallel to the floor. One at a time, take your hands to your knees and push the arms straight. Create stability in the posture by pressing your knees into your hands and your hands into your knees. Lift your sitting bones and engage mula bandha and uddiyana bandha to facilitate the extension of the spine.
Try to avoid rounding your back as you draw the scapula together and down. My teacher describes this action as "squeezing a walnut" between the shoulderblades. This is the same action that will balance the posture and protect the neck from undue strain. If you feel pressure on the back of the neck or the C7 vertebrae, exit and reevaluate your posture. If your legs will not comfortably take lotus from this position, you may modify the pose by simply crossing your legs as in Sukhasana (Easy Seat). Do not attempt to modify the posture with a half lotus position, as this will unbalance the hips and may strain the knees.