Configure covers a couple of general topics:
Hostname
Hostname is the local name by which other devices on the local network can reach your FreedomBox. Default is freedombox.
Domain Name
Domain name is the global name by which other devices on the Internet can reach your FreedomBox. The value set here is used by the Chat Server (XMPP), Certificates (Let's Encrypt), and Monkeysphere.
Language
Language for the web administration interface Plinth