A method for assembling at least a first element and a second element to form, once assembled, an external component for a portable device, including the steps of: a) making the first element; b) making the second element; c) arranging at least a first groove in the first element and at least a second groove in the second element; d) placing and holding the first and second element end-to-end with at least a third connecting element which is inserted and locked in the first and second grooves.