Embodiments of the present invention provide installation templates and methods that allow placement of various sized equipment in a finished wall or ceiling. In one embodiment, a method of forming an aperture for mounting of an in-wall component between two supports is provided. The method generally includes coupling a substrate, including an adjustable guide corresponding to the dimensions of the in-wall component, to the two supports, installing drywall over the substrate and the guide, and forming the aperture by removing at least a portion of the drywall installed over the guide.