Install kalarm by entering the following commands in the terminal:
sudo apt update sudo apt install kalarm
Description:
alarm message, command and email scheduler
KAlarm provides a graphical interface to schedule personal timed events - pop-up alarm messages, command execution and sending emails. There is a range of options for configuring recurring events. . A pop-up alarm can show either a simple text message, or the contents of a text or image file. It can optionally be spoken, or play a sound file. You can choose its appearance, and set reminders. Among KAlarm's other facilities, you can set up templates to allow KAlarm to be used as a 'tea timer'.
Homepage: http://www.astrojar.org.uk/kalarm/
Version: 4:17.12.3-0ubuntu1
Section: universe/kde