Step 1: Scroll down almost to the bottom of the story page until you see the words "+ Add Metadata." Click on those words.
Step 2: A number of new fields will open up, corresponding with the Dublin Core. Fill in the fields (you do not have to fill in all of them for the information to save).
Step 3: Once you have added your metadata, click the "Save Story" button in the bottom right-hand corner of the page to save your new citing information.