A draw.io diagram can be added at the cursor position while a Confluence page is in edit mode. In the page editor toolbar select the "insert" dropdown and select "draw.io diagram"
The new diagram dialog will now appear
If you select "blank" and click "select", the editor will open with a blank diagram.
If you select one of the template categories on the left, a number of templates will be displayed in the right-hand panel
Selecting one of the diagrams and pressing "copy" will insert that template as a new copied diagram, i.e. the existing template will not be affected.
There are two ways to insert a diagram using an existing diagram as a basis. The initial "draw.io diagram" section shows the most recently edited draw.io diagrams. Selecting one of these diagrams causes the action buttons to change (in the English locale) to