The Calendar.Events table contains a record of all the events in calendars managed by VPOP3.
An 'event' is an iCalendar event. Note that if an event is a recurring series, there will only be one 'event' in the database, not one event per instance of the recurrence.
Note that the database does not directly contain most of the data about the event, such as description, alarms, duration, etc. That data is stored in the iCalendar event stored in the content field.
If you are looking for events occurring at a certain time, you can use the 'scopestart' and 'scopeend' fields to narrow down the search, but then, for any recurring events, you must examine the iCalendar content, and process any recurring rules/exceptions in there to determine whether the event is actually occurring at the required time. This is not a trivial task!
To be able to do anything useful with this data, you will probably need to read and understand the iCalendar specification.