Hit enter to accept the changes, then hit enter again to insert them. If you see a Red Search Bar, click on the reference you need to edit, and then enter any necessary information in the popup that appears. This will bring up the insert citation dialog you saw when inserting the citation.
Now, from the Zotero tools menu in Word, select the button or menu item for Add/Edit Citation or Zotero Edit Citation. The citation should become highlighted in gray-this means you're ready to edit. To do this, click within the text of the citation (or the footnote, depending on the style you're using). You may occasionally need to edit a citation you inserted with Zotero-to add page numbers, prefix or suffix information, or to omit the author's name, for example. Zotero will add the citation at your cursor. If you see a Window listing your Zotero library, search or browse for the reference you want to cite, select it from the list, and then click OK. If you see a Red Search Bar, search for and select the reference you want to cite, press Enter to select it, and then Enter again to insert it. Zotero will add the citation at your cursor.
Then, you'll see that the insert citation dialog appears it's either a red search bar or a small window with your Zotero library, depending on your setup. If this is your first citaiton in the document, you'll first need to select your desired citation style from the document preferences window that appears. To add a citation, look for a button or menu item that says Add/Edit Citation or Zotero Insert Citation.