There are three different ways to add references to a collection in Zotero:
Using the Zotero Connector is the easiest way to add online references to your library. Once you have downloaded Zotero, you should download Connector as well. It is available as an extension for the following browsers: Chrome, Firefox, Edge, Safari.
Use OneSearch, Google, or another online search tool to locate references on your topic
Click on the Zotero button on the browser toolbar (it will initially appear as a Z, but will become a folder, book, or journal icon after using it once. The first time you will need to click on the icon again to save your reference.)
Select one or more items that you'd like to add to your library
A pop-up box will appear telling you which collection the reference is being saved in. You can change this by clicking on the drop-down menu on the pop-up.
The Zotero Connector will not be able to pull reference information from all websites. In these cases you can:
Add references by ISBN, PMID, DOI, ArXiv ID or other standard numbers:
Zotero searches several databases to find information for your reference (Library of Congress, WorldCat, CrossRef, NCBI Pub Med, and arXiv.org). Adding references using this method will not add the full text PDF
You can also add references to your library manually. You will need to do this with items that are only in print and do not come up with the standard number search. You will also use this feature when editing references.