In order to add or delete a folder from the directory of the portal created with Aruba Nuke you need, when logged in as an administrator, to click File Manager in the menu.
Beside the   icon enter the folder name which you want to create and click the Add Folder   button.

In order to delete a folder in the directory, select the folder to be deleted and click the Delete Folder   button.

Once the modifications have been carried out, in order to view the new structure of the directory click Update.