Duplicating an existing app template that's already been built in Fulcrum can be done by going to the Apps list, clicking on the More menu and then clicking the Duplicate App option. This creates a copy of the app, with all the form fields, and configurations, but the data will not be copied.

Note: If you desire the data to also be copied, you will need to export the data out of your original app and import the data into the newly duplicated app.