One of Zotero's most convenient features is its ability to find bibliographic information on the web pages you visit. For example, when you are looking at the record for a book in an online library catalog, Zotero will often show a book icon in the address bar of your browser (circled in red)
If you have selected a collection in the left-hand column of Zotero (that is, a collection is highlighted in the left column rather than “My Library”), items are saved into that collection.
Whether or not Zotero can recognize bibliographic information on a web page depends on the web page. Some websites use a standard way to provide Zotero with data (via embedded metadata). For other sites, Zotero relies on website-specific translators. Zotero works with most library catalogs, several popular websites such as Amazon.com and NYTimes.com, and many (gated) databases and websites of scientific publishers. Just look for icons in the address bar of your browser (for more information, see our compatible websites list). (Source: zotero.org)
To manually add an item to your Zotero library, click the green “New Item” () button at the top of the center column, and select the desired item type from the drop-down menu (the top level of the menu shows recently created item types; the complete list of item types, minus Web Page, can be found under “More”). An empty item of the selected item type will now appear in the center column. You can then manually enter the item's bibliographic information via the right column.
Note: When you want to create an item for a web page, it is usually easiest to visit the page in your browser and then save it to Zotero (see Saving Web Pages). (Source: zotero.org)
Importing PDF files (Northwestern)
Zotero can take PDFs of scholarly papers and query the Google Scholar database for matches.
Begin by dragging your existing PDFs into your Zotero library or use the “Store Copy of File” option from the add new item menu (green plus sign). Once they appear in the middle column, select the ones for which you wish to retrieve metadata. Right click on them and select “Retrieve Metadata for PDF”. If Zotero was able to find a match on Google Scholar, you should be all set. (Source: Zotero.org)
You can quickly add items to your library if you already know their ISBN, Digital Object Identifier (DOI), or PubMed ID. To add an item via one of these identifiers, click the “Add Item by Identifier” button () at the top of the center column of the Zotero pane, type or paste in the identifier and press Enter. (Source: zotero.org)