So, standard squat, shoulder width. Something comfortable. You're going to imagine like you're sitting back into a chair, lengthening your spine, reaching your hips back, bending your knees, and then exhale to come up. You're always going to inhale as you lower your body and you're always going to exhale as you lift any weight. In this case, the weight is your body. Exhale, pull the abs in, and come up to vertical tall spine.