Place the helmet on a flat surface.
Hold the Oakley visor over the helmet. The helmet slots should align with the holes on the visor.
Screw the Oakley visor on each side of the helmet. The screw should fit through the holes in the visor and the helmet. Tighten the visor with a screwdriver. Do this again on the other side of the visor.
Screw the other two screws at the top corners of the visor into place. The visor should now be firmly installed.
Test the visored helmet to make sure that it does not obscure your vision.