Boxes are the basic content containers for LibGuides.
A page can have multiple boxes, and boxes can be contain multiple blocks of content.
Here is Anna Burke's diagram of the relationship between guides, pages, boxes, and content:
You can grab direct box links and embed codes by clicking on the edit icon (pencil) on the top right of any box when in edit mode. Then, choose the tab for Box Link and Widget Code.
The syntax for box links is:
http://uark.libguides.com/c.php?g=[guide ID]&p=[Page ID]#s-lg-box-[box ID]