Plie squats are going to work your thigh area, which is your quads, your inner thighs, your gluts, and the hamstrings, the back of the legs.
For a plie squat, you're going to turn your toes out to the side about 45 degrees in a squat position. Your feet are a little bit wider than shoulder-width apart.
In a plie squat, you're going to sit straight down, making sure that your knees are aligned with your ankles. You're going to sit straight down in your squat. Then you're just going to stand up, keeping the weight loaded in your heels.
Again, your feet are 45 degrees out to the side. When you squat down, your knees are going to stay aligned with those ankles. You push your weight back, and then you stand straight up.
For your plie squats, you'll be working your quad, which is the front of your thigh right here, your inner thigh area, your hamstring, which is the back of the legs, and your gluts, your butt area. It works that entire thigh area.