I have generated an ER Diagram for a schema with lots of tables, by following this approach

After generating it, I re-positioned all the nodes (tables) in the diagram (Relational Model) so that they are grouped by the functionality they provide. This took me quite long.

What I want now is, to save the state of the diagram so that in the future, when the schema is moved to a new version, I just import the new tables without loosing the positions of the existing tables in the diagram.

I cannot find a way to do it. I right-clicked on my Design (in the Data modeler Browser view on the left) and selected Save Design. It created a directory with multiple sub-directories and files. But I do not know how to load that design again, which I suppose will contain the state of my Relational Model.