The Zotero Web Connector for your browser allows you to import PDFs, web pages, video, images and other content directly into your reference library from search engines and academic databases with one click. When using this option, see if it has captured any PDFs as you may need to manually add these in different databases (see the FAQ on How do I add items to my Zotero Library without using the Web Connector?).
Try using the Connector first with any database or website as it is the quickest option to add an item. When you are looking at an item record online, the Zotero Connector button in your browser's toolbar will indicate that Zotero has detected a particular type of object, e.g. book, article, website, case, or it will show a folder where there are multiple records for you to choose from.
Help video
You may also find the following short video useful (MyBeckett login required):
