If you need to duplicate a project from your account, you need to first Export the project, and then re-import the project into ParseHub.
Export a Project
Click on the gear icon button in the top-right of the left-hand sidebar in ParseHub while having a project open.
Click on the "Export" button.
Save the project on the Desktop of your computer.
Import a Project
On the projects menu from the main dashboard, click on the green "Import Project" button.
Choose the project that you saved on the Desktop to import it.
After the project loads, save the project by clicking on floppy disk on the top menu.