A method for installing a screw in at least one through-orifice of a box-type structure, including inserting a body of a first tool into the through-orifice from an external region of the box-type structure, moving the body in an internal region of the box-type structure, towards an end of the box-type structure, securing the screw to the body, the first tool comprising a link connected to the body which remains accessible from the external region during the inserting, moving and securing steps, pulling on the link from the external region until the shank of the screw is positioned in the through-orifice, and separating the body from the screw.