Put your back foot flat across the
tail of your skateboard, and put the ball of your front foot right behind your front
trucks. Ollying and kickflipping while stationary is possible, but most people find it easier to do while rolling. If you would like to learn to kickflip with your skateboard stationary, you can place your skateboard on some carpet or grass to keep it from rolling. If you prefer to learn to kickflip while your skateboard is rolling (which I feel is easier), dont go very fast at the start. Just get rolling at a comfortable speed, and then move your feet into this position.