User Manual section will get you an overall idea of user interface. See below links as functionality references.

oInstallation

oVersion Update

oStatic Page

oSnip

oUser Management

oInstall Extension

oSetting

oEmail Template

oManage Addons

oInformationSet Viewer

oServer Information

oTheme

oLanguage

oSystem Cache

oCode Editor

oFile Manager

oDatabase Backup

oChange Password