Simply install the script and leave a tab sat on the storium notifications page or the home page. Any time you get new notifications, you will receive a desktop notification.
If you want any check interval other than 5 minutes you need to edit the intSecs variable in the script file. It should be easy to locate and figure out :) UI for changing settings to come in future versions.
And now it refreshes the page if it finds a change, after a delay (default 30 seconds).