Follow these steps to duplicate an existing portfolio:
Open the Portfolio editor.
Click the portfolio selector in the center of the menu bar.
Choose Manage portfolios.
You’ll be redirected to the Portfolio manager.
Hover over an existing portfolio’s thumbnail.
Click Options (⋮ in the thumbnail's top-right corner.
Choose Duplicate portfolio.
Important: Allow some time for the duplication to be processed! Do not refresh or close your tab before the process is over!