Lower the fixed barrel over the main PCB assembly, lining up the holes on the side with the holes on the side of the intermediate barrel.

The fixed barrel should be oriented so that the "IMAGE STABILIZER" text should be lined up with focus window further down on the lens.

Be very careful lowering the fixed barrel so that you do not damage the main PCB assembly or ribbon cables.

Screw in the four Phillips #00 screws around the sides of the fixed barrel.