Ahh the squat, often neglected but so good for you. If you have trouble doing the yogi squat try a block under the hips to help stabilize you. If have trouble getting your heels on the ground place a block under your heels, or a bolster or rolled up blanket. There are also several variations of this pose. My mom loves wrapping her arms around and clasping them behind her back.
How do you take your malasana?