Most beginning students can't comfortably rest their feet on the floor (nor is it advisable for the neck - I have seen overzealous practitioners pinch nerves in the cervical spine). Please practice this pose with an appropriate prop as mentioned above. Brace the back of a metal folding chair against a wall (if you like, cover the seat with a folded sticky mat), and set one long edge of your support a foot or so away from the front edge of the seat. The exact distance between the chair and support will depend on your height (taller students will be farther away, shorter students closer). Lie down on the support with your head on the floor between the blanket support and the chair. Roll up with an exhalation, rest your feet on the seat (and check to see that you are neither too close nor too far from the chair), then lift into Salamba Sarvangasana first before moving into Halasana. In this pose (and its companion, Salamba Sarvangasana) there's a tendency to overstretch the neck by pulling the shoulders too far away from the ears. While the tops of the shoulders should push down into the support, they should be lifted slightly toward the ears to keep the back of the neck and throat soft. Open the sternum by firming the shoulder blades against the back. hth
