The left column displays the different collections that organize your library
The center column contains the list of references in the selected collection
The right column shows the bibliographic information and notes related to each reference
Buttons
At the top of the Zotero window are a series of buttons
The New Collection... button creates a new collection in your library. Collections are discussed in more detail here
The New Item and Add Item(s) by Identifier buttons let you add different types of references to your library or collections. Adding items to your Zotero library is discussed in more detail here
The New Note and Add Attachment buttons let you attach additional files to items in your library. Attaching files is discussed in more detail here
You can search your Zotero library using the search field or the Advanced Search button