To do Squat Pulses, stand with your feet between hip-width and shoulder-width apart. Then sit your butt back and sink into a squat. Keep your chest up and your core braced. You can reach your hands out in front of you or keep them in at your chest.
From the squat, pulse up and down, coming up toward the top of the squat and then sinking back down to about parallel. Keep your chest up and your heels down as you pulse. Make sure you continue to sit your butt back as you stay in the squat and pulse.
Stay within that working range, sometimes doing bigger movements and sometimes doing smaller pulses right around the bottom of the squat.