The video shows in turn:
Turn pink screw anticlockwise to release blue slider.
Push the pink screw to move the blue and green sliders (rough adjustment).
Turn the pink screw clockwise to raise the blue slider for fixing the blue slider.
Turn yellow screw to move green slider (fine adjustment).
Cyan pin is for preventing axial motion of the yellow screw.
Orange screw is used for fixing the green slider after adjustment if needed.
This mechanism finds application in caliper-squares.