There are few instructions for this sublime pose (that we long for in the middle of a difficult class, or at the end of a long, hard day.) The only important thing is to be in a comfortable position, eyes closed, lying restfully on your back, so that you do not fuss with the body. Let back, neck, legs, arms, shoulders lie open, long and heavy with gravity. Palms are open, feet and legs roll outward. If you are there for a long enough period, and you know your back will ache, place a block or pillow under the knees. Support whatever needs supporting so that you can turn inward to your breath, to this moment of ending and surrender.
Physical places that often need conscious attention are the eyes, tongue, and jaw. Take a few breaths at the beginning to mindfully breathe through head channels, including ears, nose, back of neck, and around forehead furrows, or third eye. If class has been stressful for your ego, pay attention to an anxious stomach, and any feelings of being less than. In time, your Practice will not allow that, but often in the beginning, we all suffer from some form of not being as fabulous as we wish. Let it all flow into the river, washing through the body, belly breathing that balm in Gilead.
Ideally, you spend 5 minutes for each 30 minutes of class. That is becoming rare, but when you do come out and up, roll to the side and slowly sit. Let the head be last, keeping your eyes closed if possible. Be aware of how different you feel now -than before.
Health Notes: This is a master pose, good for whatever ails us. I have used it for depression and anxiety, insomnia, and nervous jitters. It is a great reminder of releasing ourselves to Cyclic Grace. It is like starting over with each New Moon, the time when Sun and Moon come together in dark splendor to give birth to the coming 28 days. Each Savasana can be that dark, dying Grace of letting go to beckon birth, a re-awakening. It is good to know that this pose is also called Mrtasana. or death. Much more defined than corpse pose. No?