Squatting is one of the easiest lifts to learn and perform. And break parallel, if you're squatting to parallel you'll be squatting high for sure.
Without a bar, stand with your feet slightly wider than shoulder width. Play around with your stance mind, it will be dictated by height and limb length in relation to your trunk (torso). Don't worry about how you squat down, just drop to a full squat and lean forward to maintain balance. Clasp your hands together and push your knees apart with your elbows. Try and stay in that position for 20-30 seconds. then stand up. Do this a few times to open up your hips and give your self some idea of what the bottom position should feel like. As you play around with your squat stance, you'll find that as you bring your feet in closer you'll get a full squat easier, move them out until you find that you can't hit depth. You'll mostly, naturally, find a stance that you like
Once you've played around with hitting depth, the rest has a lot to do with pulling your shoulder blades together and holding them there through the lift and making sure the bar isn't resting on your neck, you'll have a natural groove to place it in just above your rear delts. Squeeze the bar hard with your hands at all times, and remember to take a deep breath and brace your abs when you unrack the bar.
Step back, look straight ahead, not up, deep breath and lift your torso and shift your hips back a few inches as you start to drop into the squat. After about six inches of starting the lift you should be able to just go down in almost a straight line with your torso going between your legs, remember to push your knees out hard. once you break parallel, maintain that forward start and push up and backwards through the bar, it will keep the bar over your centre of gravity. You should feel like you're lifting your chest as you ascend. Presto, you've done a full squat. There are plenty of good instructional videos on youtube, try and look for weightlifters coaching the lift. Bodybuilders will squat high and won't typically keep a tight back, powerlifters might screw you over because if they lift in 'gear' (supportive equipment), it will alter the way they squat. They'll sit back a lot more instead of going down.