I’m a big fan of squats (as you can see in the video above) and recommend it as an exercise whenever my clients are looking to build their legs and core strength.
Why? Because it is reasonably safe and also, if you want to shape your buttocks (as well as your legs), then it is the right exercise for you.
So, first of all, localise the muscles that you are going to use for this exercise. These will most likely be your quadriceps and your glutes' (though of course your core muscles are also used when squatting), as these are actively engaged to secure a good posture during the exercise.
Once you have so focussed on the muscles that you will be exercising, you can then go under the barbell and squat.
Firstly, grasp the bar firmly with your hands at a comfortable width and with your elbows back.
Next, inhale deeply , slightly arch your back by rotating the pelvis forward, contract the abdominal core, look straight ahead and remove the barbell from the stand.
Then step back with your feet parallel, bend forward from the hips (whilst avoiding any rounding of the back).
When your thighs become horizontal to the floor, straighten the legs and lift the torso to return to the initial position.
Then exhale at the end of the movement!
To build an effective combination of exercises you can add some jumping lunges into your routine, the idea being to include some free movements to the mix for maximum results.
Finally, squats can be quite demanding physically, so if after your you feel exhausted, just take a regular break before moving on with your workout.