How to: Add a citation with VisualEditor
Let's try adding citations through VisualEditor. You may want to open up a sandbox page to follow along.
Click "edit" above the section or article you want to edit.
Within VisualEditor's toolbar, you'll find the "Cite" button. You can simply paste a URL, and the VisualEditor will try to sort out all of the fields you need. Be sure to review it, however, and apply missing fields manually (if you know them). You can also add books, journals, news, and websites manually. That opens up a quick guide for inputting your citations.
If the page already contains a citation you want to use again, you can!
To re-use an existing reference, place your cursor in the body of the text where you want to add the new reference for that citation. Then open the "Cite" menu and find the "Re-use" item.
To edit an existing reference, use the "edit" button to open VisualEditor. Click on the bracketed number for the source you want to edit. You will see an icon for the type of reference (book, web, news, etc.) and an "Edit" button to the right.
Clicking on the "Edit" button will open a dialog where you can do exactly that.
Remember to leave a description of your edit in the edit summary, such as "added reference," and then click "Save."