For supplying individual quantities of flat and in particular diverse part products to a serial further processing, the part products are arranged in a row of part product groups (7) in a preparatory step carried out before the supply step (e.g. supplementation), and the row (2) is fashioned into a “first-in-last-out” storage formation, such as a roll (5). Within the row (2) the part products or the part product groups (7) overlap or are spaced from each other. For stabilizing the part product groups (7), adhesion between the part products within the groups may be enhanced; for stabilizing the storage formation, the part product groups (7) may be reversibly connected to each other. For supplying the groups to the serial further processing, which may succeed the preparatory step at any time or place, the storage formation is dissolved and the part product groups are supplied to the further processing directly from the storage formation. The preparatory step is completely uncoupled from the supply step, which simplifies the method and the installation for both, the supply and the further processing.