I am sometime not sure where to ask questions 
Gnome, Ubuntu, Budgie forums etc
I don’t have alert ( notification) when setting up appointment in my Calendar
I would like to get a pop up window or at least a notication ( system tray) to notify me of appts for which I choosed to receive an alarm/notification
JF
I checked the Reminder when scheduling something…
The notifications are provided by evolution-alarm-notify which is part of evolution, not evolution-data-server. So you need to have evolution installed for them to work. However there are some plans to move this functionality to gnome-shell: gnome-shell#155. I think this issue can be marked as a duplicate of the gnome-shell issue. Installing evolution should work around the issue in the meantime.
If Evolution is not installed, GNOME Calendar event reminders / alarms notifications popup or sounds will not work (#239) · Issues · GNOME / gnome-calendar · GitLab
congrats for digging that out.
Curious to see the move to gnome-shell - not very clear how that will impact non-gnome shell based desktops