Next goes the Advanced group with the Users/Groups page. Easy to guess, you can specify user accounts here. The accounts can later be united into groups.
The rights to access network folders can be assigned to the created users and groups on the Network Access page.
The FTP server page is where you can set up the namesake server.
There are quite a lot of options here. You can choose the encoding to be used by the server (from a very long list), create rules for users to use the FTP server by, and specify the basic parameters of the server such as speed limitation, server port, etc. We guess the only significant drawback here is that you can only open one folder for each user to access (this goes for the previous page as well).
The UPnP AV Server and iTunes Server pages are for setting up the corresponding servers. You can only chose the folder for indexing and enable/disable the necessary service.
It is unclear what an entry-level NAS might need a DHCP server for, but its settings are located on the DHCP Server page. The settings are very scanty, though. You can’t even reserve IP addresses for specific MAC addresses.