Please go to Appearance > Install Plugins, install/activate the “Yoast Duplicate Post” plugin
Go to the Pages(or Posts/Portfolios) list, you will find the “Clone” link below each page. Click “Clone”, it will duplicate the page.
There is not the “Clone” link in portfolio list. Please go to “Settings > Duplicate Post: Permissions”, pickup the “Portfolio”
We don’t suggest you use other duplicate(or clone) plugins. They mostly don’t work well with the BM Content builder.