The GNOME Desktop provides the functionality of any traditional operating system desktop. You can drag files, programs and directory folders to the desktop; you can also drag those items back into GNOME-compliant applications.
IMPORTANT: The GNOME Desktop is actually provided by a backend process in the GNOME File Manager. If, for any reason, that backend process has stopped running you may start the GNOME File Manager again and your desktop will be restored. Even if you do have to do this you do not need to keep the GNOME File Manager window open to enable the desktop.