2.1 Turn clockwise with a hexagon wrench until it does not move at the scale line 16mm. Hinge can open to 75°automatically.
2.2 Open the hinge to 120°manually. Turn counterclockwise with a hexagon wrench to the scale line 4-8mm.
2.3 Clamp the hinge on the profile and use a drill with ¢3-¢3.3 to drill the holes on the profile in advance. After drilling,install the screws .