Locate the overhead projector's lateral positioning arm and lateral positioning plate. The lateral arm may only support the projector head, or it may support the entire projector.
Loosen the screws securing the projector's lateral positioning arm to the lateral positioning plate. Depending on your projector model, you may be able to remove these screws either by hand, or by using a Phillips or flathead screwdriver.
Adjust the projector's lateral position as needed.
Tighten the screws you loosened in Step 2 to secure the projector in its new lateral position.