A method of forming an assembly including a first workpiece having a surface provided with a mortise and a second workpiece provided with a tenon inserted into the mortise joining the workpieces together in which the second workpiece is disposed in a certain orientation relative to the first workpiece to provide a certain disposition of the workpieces when joined together, generally consisting of providing identifying marks on the surface of the first workpiece and the tenon of the second workpiece at locations assuming a certain disposition when the second workpiece is disposed in a certain orientation and the tenon is registered with the mortise; positioning the second workpiece relative to the first workpiece wherein the second workpiece is disposed in the certain orientation relative to the first workpiece, the tenon is registered with the mortise and the marks are disposed in the certain mark disposition; and displacing the second workpiece toward the first workpiece and inserting the tenon into the mortise.