When you select the Create New Diagram option while adding a 
Simple Diagrams macro, you'll be able to generate a new diagram and insert it directly into the desired page in Confluence.
Once you click the Create New Diagram button, a new diagram is generated, stored in the page's attachments, and opened in the editor:
After completing your work on the diagram, click the Save & Exit button to save the changes and exit the editor, or click Exit to discard any changes made (if any) and leave.
Following that, you'll see a preview of the created diagram.
Note: saving the diagram will update file version in attachment, but won’t raise page version.
