New Menu Item: Article

Select the "Standard Article Layout (single article)" type to get to the details screen above. You'll notice in the Parameters where the mousepointer is, the "Select" button. Click this, and you get the modal pop-up below here:

From the articles listing, filter by section or category to make finding the one you're looking for easy, just click the title and you've got it!
Simple as can be. 

New Menu Item Creation: way cool!

Here, you see the new selection screen for adding a new menu item:
* click on the type of item you want to add,
* tree will expand to reveal sub-nodes to select from (if existing).
First example below here is adding a Newsfeed Category List.

If you change your mind / notice you picked the wrong type, just click the "Change Type" button to go back to the screen above.

Very simple to use. Well done guys!