Summarize the following:
You can use a yoga mat or a gymnastics mat; either way, you want a mat that is going to give your support and cushion while you attempt your headstand. Lay your yoga or gymnastic mat lengthwise in front of you.  If you are not confident enough to practice your headstand freely, you can place your mat up against the base of a wall. Anyone who has never attempted a headstand should first practice against a wall. Practicing against a wall will help you find the initial balance and strength needed to hold a free form headstand. Kneel onto your mat. Bring your upper body down to the mat so your hands are out in front of you. Your body should now look like a table, with your knees lined up with your hips and your hands about shoulder-width apart. Bring your elbows down to rest on the mat.

Summary:
Position your cushioned mat. Position your body like a table top.