in the room that you use for zazen, spread some thick mats and place a firm, round pillow on them. Sit on the pillow with your legs crossed either in the full-lotus position or in the half-lotus position. This means [in the full-lotus position] that you place your right foot on your left thigh, and your left foot on your right thigh. In the half-lotus position, you just put your left foot on your right thigh [with the right foot on the mat beneath your left thigh].