Selecting different calendars or reminders

What I did: I have two different calenders and 4 reminders setup on my MacBook.

What happened: When I try to schedule from Agenda the dropdown did not give me any options for different calender or reminder. Agenda schedule it in the default calender same goes with the reminder.

What I expected: I should be able to select different calender or reminder from Agenda.

Things that might be helpful to know (Agenda version, OS and model, etc):

Are the calendars and reminders visible in the system Calendar and Reminders app, or are you using a 3rd party app?

I am using a macOS calendar. I have two calendars configured on my Agenda app. When I try to schedule, Agenda does not give me the drop-down options to select my calendar. This issue is the same for Reminder.

Are these read-only calendars perhaps? Can you schedule to them in the System Calendar app?