Adding a sheet
You can add a sheet by clicking the “+ Add Sheet” button at the top of the sheets preview panel.
Copying a sheet
In the sheet preview panel, hover over the sheet you would like to copy, then click the “Copy sheet” icon.
Copying a sheet from a different diagram
Please open the diagram you want to copy elements from and a blank diagram.
Select everything on the sheet you want to copy by using the keyboard shortcut Ctrl + A (Command⌘+A for Mac), then copy all objects by Ctrl + C (Command⌘+C).
Go to the target sheet of the new diagram and paste the copied contents using Ctrl +V (Command⌘+V).
Deleting a sheet
In the sheet preview panel, hover over the sheet you would like to delete, then click the “Delete sheet” icon.
Information on Adding, copying and deleting sheets on Editor versions before 6/27/18: https://support.cacoo.com/hc/en-us/articles/206564248-Adding-copying-and-deleting-sheets