When a Sagan is shared directly to you by someone, it is added to the "Shared with me" tab in your Sagan palette. Here's how to find it:
Click the Sagan Palette button, which resembles a small home, in the upper left.
and select the Shared With Me button
To explore the Sagan without adding it to your map, simply double-click on the Sagan's Icon and it will take you directly into the Sagan.
If you are looking for a particular Sagan, you can type in the Search Shared With Me area for the name or associates keywords.
If you would rather look at the Sagans as a list, select the List icon at the bottom of the page to change the viewpoint.
If you do want to add a Shared Sagan to your Map, drag it into an open space
Shared Sagans are highlighted in green once they are dragged onto your map.