You want to start with your feet probably about shoulder width apart. If you're more comfortable a little wider or even externally rotating your fit a bit, just find place that's comfortable for your hips and make sure that your knees always track. A good rule of thumb is to think about your knees going right in between your big toe and your second toe. When you're doing a squat just watch out that your knees are not adducting and collapsing in or abducting and going out. You want to try to maintain the knee in a neutral position