From the drop-down in the the upper left choose Editorial / Assets...
NOTE: Not sure how to access BLOX Applications? Click here
(Not sure how to access BLOX Applications? Click here) and open your Article Asset. Click on Related.
Under Related / Child Assets, click on Add and navigate to Other Apps / Calendar. If you have not created the Calendar Event yet, click on Event (need help creating an Event, click here). Otherwise, click on Find Asset. This opens the Calendar Event Search window.
Note: Calendar Assets will appear as a Related Sibling and Parent Asset on the right rail even if there is not a Related Child Asset used.
If your Event is not listed, use the Search Terms to find it. Once you've located the Event(s) you need, select them and then click on Add Selected Assets at the bottom.
Notice the Event(s) will be added to the Article Asset as a Child Asset. Click on Save and Close. The Events will be positioned to the left of the Article Asset content (Flex).