Install agenda.app by entering the following commands in the terminal:
sudo apt update sudo apt install agenda.app
Calendar manager for GNUstep
SimpleAgenda is a an application to manage your calendars. It handles both local and remote (webcal) calendars. Calendars can be shared with other programs like Evolution, Dates, IceApe Calendar and others. The following features are available: . * Multiple agendas. * Handle both events and tasks. * Support for local and remote (ftp, http) iCalendar agendas. * Monthly calendar, day view, summary and tasks view. * Create, resize and move appointments easily. * Export individual elements as files and to the pasteboard. * Import .ics files. * Simple text search. * Alarms with multiple backends.