To do Tuck Jumps, start standing with your feet close together. Bend your knees slightly as you hinge over and push your butt back to load your glutes. You can swing your arms back if you want a little extra help jumping up.
Then jump up off the ground, tucking your knees in toward your chest as you jump. Straighten your legs back out as you go to land on the ground. Slightly bend your knees as you land and jump right back up, tucking your knees up toward your chest.
Do not squat as you land. Your goal is to load your glutes by slightly hinging and then jump up and tuck your knees up as high as you can.