Select the citation you want and press Enter/Return on your keyboard. If a reference appears in multiple libraries, you'll see both copies of that reference and will need to choose between them.

You can cite from My Library or any of your group libraries when citing while writing. In the red-bordered Z bar that pops up, search for a word (author name, title word, etc.) to locate the desired item in your Zotero library. Once again, put the cursor where you want your citation and tap Add/Edit Citation. After that, you'll be able to select your desired style for the document in Microsoft Word. Search for your desired style and click on the name when it appears in the list. Zotero's Preferences will open to the Cite menu. If you need a style that isn't listed, tap Manage Styles at the bottom of the box. You can always change the style by using the Document Preferences button.

The Document Preferences box will appear. Put your cursor where you wish to insert a citation. Tap the button to reinstall the Microsoft Word Add-in. In Zotero, go to Preferences, select Cite, and choose the Word Processors tab. If you don't see the Zotero tab, you can reinstall it. Zotero must be open at the same time, but you don't need to be connected to the internet. To add citations and references to your Microsoft Word documents, use the Zotero tab in the ribbon.

How to use zotero in word to reference