Creating an outlook add-in for calendar

Question

Hello,

I'm looking into making an add-in for Outlook, that's used when scheduling an event in the calendar. However, nowhere in the documentation I can find information about an add-in in the calendar, only in the mailbox.

Also nowhere else on the internet I can find proper explaination about how to do this. The only issues I can find on websites like StackOverflow are over 5 years old and written in C#.

Does anyone know where this information can be found? It would help a lot!

Thanks in advance.