
Creating groups allows you to break a large library into subsets according to various tasks you might be working on, or themes in your research. EndNote allows only two levels of hierarchy when it comes to groups: Groups and Group Sets. A group set allows for multiple groups to be clustered under a single heading.
You can add references into a group from the All References folder or Recently Added and Unfiled folders and you can also add from other groups. To add a reference or references, select them and then either drag them to the group or right-click on the selected references and choose Add References To.
Groups can be moved from one group set to another: select the group and drop into another group set. You can also delete a group or a group set. Deleting groups and group sets will not delete the references in the EndNote Library. The references are still kept in the All References folder. Deleting references from a group does not reduce the number of references in the EndNote Library as well.
Smart Groups are created automatically by EndNote according to the search criteria you create. When new references are added into the EndNote Library, the references matching the search criteria will go to the Smart Group automatically.