Please notice the widget on your right. Click on the + sign to open the tree of exclusive articles if it's not open yet. If you want the articles from the Opera In-Depth project, click on its + sign and the operas will be listed. Keep clicking to read the article of your choice.
Any time you get into a message "no content" when there are sub-branches of the tree below it, don't get stopped by it, the content *is* there, just keep clicking down the tree to get to it.