What is the difference between recurring and multi-day events?

Recurring Events:

Think of recurring events as a lecture. For example, you have an event called "Evolution 101" which is a recurring event that recurs every week, on Mondays, from 10:00 - 14:00. Every week, the "Staff" (employee) provides the same lecture, so there'd be no reason why a single customer would want to book the same lecture for X number of weeks (because it is the same lecture every week).

Because of this, every recurring event is considered a separate event, and when a customer books one event, they are not automatically added to all recurring events.

Multi-Day Events:

You can create an event that spans between Monday and Friday, or that includes multiple dates (November 23rd, then November 25th, then December 12th, then January 2nd, and so on). Think of this as a course that either offers different content on every date, or it continues from the last date. For example, a multi-day event that happens on November 22nd, November 29th, December 6th, December 13th, and December 20th is a 5-class CSS course. On November 22nd, you'd learn basics, on November 29th, you'd move to another stage, on December 6th - to another stage, and finally, on December 20th, you'd complete the course.

A customer would book this event to register for the CSS course, and they would automatically be assigned to all 5 dates within this one event.