Collections
You can create collections (folders) within your library to organize items associated with different topics or projects. Just drag items from the center pane over a folder to add them to a collection. If you select a collection before searching for sources, any items you add with the connector will be added to that collection.
Notes and Tags
With an item selected, you can use the tabs in the right-hand pane to add notes about the item, or to add tags (keywords) you wish to associate with the item.
The Search feature will search all the item information, your notes and tags, and the full text of items if it is saved in the Zotero library.