When Zotero is open, you can sort your citations into folders.
At the top left is a Folder button with a green plus sign. Click this to create a New Collection.
Create collections to organize your references. Collections are like file folders on your computer. Your references can be stored in multiple collections at the same time, when making updates or notes on a reference it will update in all places.
If you delete a citation from one folder, it will not disappear from all your folders until you delete it from every folder you put it into.
It's easy to create a bibliography from your Zotero library.
Select the references or collections you want to include. Hold the control key and click to select multiple items.
Right-click one of the selected items and choose Create Bibliography.
Choose the bibliographic style you want (MLA, APA. Chicago and others) and select the output format (RTF, HTML copy to clipboard or Print).
Or you can just drag and drop references from Zotero into your document. Highlight your citations of choice and drag them.