Do a search on Google or your preferred search engine for the subject of the Wikipedia article that you want to create a citation for.
Find a website that supports the claim you are trying to find a citation for.
In a new tab/window, go to the citation generator, click on the 'An arbitrary website' bubble, and fill out as many fields as you can about the website you just found.
Click the 'Get reference wiki text' button.
Highlight, and then copy (Ctrl+C or Apple+C), the resulting text (it will be something like <ref> {{cite web | .... }}</ref>, copy the whole thing).
In the Wikipedia article, after the claim you found a citation for, paste (Ctrl+V or Apple+V) the text you copied.
If the article does not have a References or Notes section (or the like), add this to the bottom of the page, but above the External Links section and the categories:
