The default setting within a watchlist or company's newsfeed is to display articles by relevance. The more relevant to your topic filters and companies, the higher it will be within your list of news articles. Relevance is shown next to the date above the article in the form of a signal bar.
You can change the order in which your newsfeed is sorted by clicking on the "Sort Options" tab at the top of the newsfeed, then selecting one of the four options: Relevance, Date (most recent), Triggers and articles published in a certain date range (default 30 days, but can range from 1-60).
Triggers are shown as coloured boxes found above an article which help to identify positive and negative news, and are intended to assist you in spotting opportunities or risks in your accounts and allowing you to take prompt action. Sorting by triggers will group triggers of each type together, with articles matching no triggers or those marked as low relevance moved to the bottom of the newsfeed.