Start by performing a squat then return to standing and do a jumping jack by jumping your feet wide and hands together. Return to standing, perform another squat and repeat!
Tips for a strong squat: Start standing with feet about shoulder width apart. Lower hips until thighs are parallel to the ground (or as close to this as you can). Squeeze glutes and push into your heels to bring yourself back to standing. Be careful to keep your gaze ahead of you, not to let your upper body lean forward, and prevent your knees from bowing inward or outward. You should never be on your toes while performing a squat.