You get it on a blog, then another blog reports on it, using the first blog as the source. Sooner or later a "reputable" news org "reports" on it, using the blogs that have reported on it as their source. Eventually, TV will pick it up and then it's officially "real."
It's all garbage, and besides whatever political motives they may have, a big motive is clicks. Everything is driven by clicks. They get paid by the click. It's all BS.
I’ve just started reading Sharyl Attkisson’s new book The Smear: How Shady Political Operatives and Fake News Control What You See, What You Think, and How You Vote. It looks like it will cover some similar themes.
This same false-chain-narrative was the basis of the Urinating Prostitutes Trump Dossier, eventually sent to McCain, who bumped it to the government. Presto! A alse story becomes gospel.