You may browse the available classes by entering the browse page . To contribute you have to subscribe by identifying yourself with your e-mail address. The system will send your initial password to that address so you may login . Then you have to create folders for your classes . Only then you may upload the files to the folders of your classes.
Users have to be subscribed to be notified by e-mail when a new class is added or updated.
Subscribed users may also ask the system to do not send notifications .