The diagrams are saved in the directory schema. You can create a new schema or open (load) an existing schema. When you define the various elements that make up your diagram, you can save it by choosing "Save ..." or "Save as ...". The list of existing diagrams can be obtained by selecting "Diagram library." Double-clicking a row in the table in the diagrams library, you can open the corresponding diagram.

"Description" sets the name and description of the diagram

"Associated project library" lists of projects to which the current diagram is associated