Hang either a painted sky backdrop or a cyclorama (a special piece of fabric designed for projecting lighting effects onto) behind any other stage set items. This will likely be the same background for most of your performance, unless you have the technical capability and budget to change it easily. Coordinate with your director and scenic and lighting designers to ensure the backdrop works throughout the show.
Place the light for the Batman effect on a floor-mount base, then place this where it will be during the show. To get the right size and angle of light beam, this light will most likely need to be onstage. Coordinate with the crew to make sure the light can be placed onstage when needed and removed when not needed, or find a place for it where it can be permanently onstage.
Turn on the Batman effect light and focus it on the backdrop or cyclorama. Adjust its position for the best sizing and make sure it can be seen from the audience.
Place all other set pieces so they do not interfere with the beam projecting onto the backdrop.
Place a smaller set piece or furniture item, such as a crate or garbage can, between the light and the audience to hide the source of the light. A special set piece can also be created for this purpose, such as a portion of a building exterior or false foliage, often called a ground row. Keep all set pieces far enough away from the light so they will not overheat due to the light's heat when it is turned on. This is generally 1.5 feet minimum, but materials that are not flammable may be placed closer.
Coordinate with the director, other designers and stage managers to ensure that all actors know where the lighting instrument and any specialty set units are during the scenes in which the Batman effect will be used, so they do not run into these materials or stand between the light and the backdrop, disrupting the projection.