If you no longer need an article, or don’t want it to go out yet, you have two simple options. (2 steps, about 1 min)
Open the article and, in the Publishing panel on the right of the editor, choose Switch to draft. The article stays, but it will not go out until you publish it.

In the Calendar, click the article and, at the bottom of the Article details panel, choose Delete this article (the rows of the Articles list also have a Delete button).
