oops. ive been using it from the start ;-)
for alarms, you use the clock.
calendars will just give you notifications.
It is possible to set alarms too in Agenda, but I haven't got them to actually go off in the Cosmo yet. (That they apparently haven't "noticed" that, and the problem in general with snoozing/stopping alarms from Agenda, and thus not corrected it either, is kind of strange. This problem has existed since the beginning in the Gemini!!) I have tried only a few times with a few different entries, and it doesn't always go off in the Gemini either, so I might have been "unlucky" with my entries in the Cosmo. (Copying an entry and changing it is the best way to ensure you get the alarm "correct" in Gemini also, so maybe it carries some settings that are "invisible", and not always get set, as well??)
But it is also a NIGHTMARE to navigate in Agenda. Despite the fact that it is made by Planet you really need to use both the keyboard AND the screen to navigate: There is no way of entering time in 24-hour format, you HAVE to use am/pm, which is both unnatural for me as a Norwegian, and makes it impossible to just type in the time, at least when it is a "pm-time" as it starts with am as default. (Luckily it at least DISPLAYS time with 24-hour format, but it can only display start time and not end time, even in day-view it only displays start time, although it "marks" the hours it spans, but it marks an hour when it spans just one minute of the hour, and will not help with overlapping entries either...) And to make matters worse; it is often extremely difficult to get it to register screen presses!!
I have been kind of surprised that NONE of these problems seems to be registered by Planet; the latest update (in Play store) for Agenda is 5th of October 2018, and NONE of the issues I have listed here were addressed in that update. (And they are present in the Cosmo as well, so even though it might be a newer version none of these issues are corrected there either)