Inside the itinerary builder, there is an edit button next to "+ New Event".
This will allow you to do things like
Save Items to Library
Save Items to Library as Multi-Event (aka Day)
Tag Individual People (for group itineraries)
Side Note: You'll need to have at least one event checked in order for this option to appear.
You can also rearrange events with the edit button.
Related to this article:
What does tagging people mean?
What is a multi-event?