To do Squat Jumps, stand with your feet between hip-width and shoulder-width apart. Sit your butt down and back into as low a squat as you can with good form (aka your heels stay down and your chest stays up and your knees don’t cave in).
You can then swing your arms back as you squat or reach your hands down to touch the ground.
Then explode up out of the squat and jump as high off the ground as possible. You can swing your arms and reach your hands overhead to help propel you up. As you jump, extend your body fully.
As you land, sink right back into the squat so you can explode right back up. Do not land with your legs straight. Make sure to bend your knees as you land and try to land softly to protect your knees.
Beginners may need to rest between each rep; however, that doesn’t mean landing with your legs straight. You should never land with your legs completely locked. Bend your knees to help you absorb the impact of landing even if you pause between jumps.
Beginners can also start with a quick Basic Bodyweight Squat and even come up onto their toes as the stand up instead of completely leaving the ground. If they have good mechanics, they may want to leave the ground but not jump as high.
To make the move harder, jump up and sink right back into the squat to repeat as quickly as possible. Really focus on a soft landing and then exploding quickly into as high a jump as you can.