The best way to organize all of the references in your library is to create groups. There two main types of groups in EndNote.
To add references to a group, click and drag references into the group. (You can highlight more than one item at a time by using your “Ctrl” and “shift” keys.)
If a reference won’t drag into and be added to a group, click away to a different location in the left-hand navigation plane (like “all references,” “unfiled,” or “trash”). Then try again.
Please note that you can delete references from a regular group (not smart groups) without deleting them from your library. Just make sure that on the left EndNote navigation panel, you are in the group’s folder view when you delete the reference. (A confirmation box will pop up to ask you to verify.)
You can also delete a regular group from the left-side navigation plane without any of the included references being deleted from your library.
Please note that it is not recommended to create smart groups from keywords unless you are familiar with the keywords in your references. Most keywords in EndNote are assigned by the database, catalog, or website that you got the item from. Articles on the same topic, but saved from different locations, will have different keywords (“children” versus “adolescents”), or some references might have no keywords (e.g. Google Scholar does not save keywords). The closest way to creating a smart group by keywords is by using the “any field” or “any field and PDF with notes” fields.
Please note that deleting a reference from a smart group will delete that reference from your entire library. EndNote will not give you a pop-up confirmation message that the reference will be deleted from your library. If you delete a reference by mistake, you can retrieve it from your trash (in the left-hand plane). You can, however, delete the entire smart group without any of the references being deleted from your library.
References not in Groups
All references in your library that have not been added to a group are in your "unfiled" folder.