4 sets
Set 1 12 light reps
Set 2 10 heavier reps
Set 3 10 heavier reps with 3 second slow count on descend
Set 4 8 heavier reps with 2 second slow count on descend plus 1 second pause at the bottom of the squat

Note: Increase weight each set, pay attention to the slow count tempos. On the last set of 8 reps, breath and tighten up your core, descend, hold position at the bottom of the squat for 1 second, and back up as you exhale. Repeat for every rep on that last set. Rest 90 seconds between sets.