Part 1 GB single leg squat progressions.
Use the Mastery chart to pick ONE for your pistol squat progressions. You should be able to move smoothly through the work, mobility cycle for the suggested number of cycles. Although you should be working hard, If you MUST stop and rest, or your range of motion is incomplete, then then you need to move to a lower step.
Part 2: Weighted single leg squat
Do five sets of 6 alternating weighted pistols. (3 each side)
Part 3: Using pistol functionality.
Spend some time experimenting with a functional pistol movement.