Set up in a split stance, with your front foot elevated on a stable surface. Toes pointing forwards, and spine neutral.
Start bending the front knee, and stay upright as you descend into the squat. Drive the knee forwards over the toes, and tracking in line with the foot.
Pull yourself as deep as you can, and pause in the bottom position - keep driving the knee forward, you should feeling your shin & the top of your foot engaging.
Then push through the heel and return to the start. Repeat for repetitions & switch sides