The position on a surfboard

Put your feet on the tail of the board.
The navel should be at the centre of the board.
Your ribs and thighs touch the board.
The shoulders are held high, the upper body is upright and the lower back is contracted.
You should be looking upwards and not towards the board's nose.
The position will vary slightly depending on your size and the board.
The most important thing is to find a balanced position (too far forward = the nose will dive into the water, too far back = you'll slow yourself down).
The flatter the board is, the better it will glide (tips: keep your shoulders high).