Right-click the desired node to create a folder beneath it.
On the left side of the "Overview" page, an Action menu will appear.
Click the "Create" button.
Select "Folder"
Found in the action menu after selecting "create"
Specify a name for your folder
Positioned at the top of the form builder
Save your new folder
You can now see a new folder with your specified name where you can create additional forms and folders beneath it, continuing the same process.