Calendars can only display the dates from a single Date field in an object.
For example, let's say you have an object called Events and it includes an Event Start Date and an Event End Date. You would only be able to show one of the date fields on your calendar.
If you want to show start and end dates/times, then you can store that information within a single date field, Event Date, by enabling the Calendar Options:
With the Calendar Options set to Yes, you can now enter a start and end date/time within a single date field. You can also set events to be "All Day" or create repeat events.
Note: The calendar options are available only for calendars. You can't display start and end dates or repeat events on a table or other view.
For steps on pulling out the end date/time to be used outside of a calendar, take a look at this article: How to Extract the Start and End Dates from a Date Field.