You could have them look at Atom through the dev tools, where they would see that the construction of Atom is the same as a web page. You could have them look at the API and write a short
init.coffee script. You could have each of them write a snippet that expands into a comment block with their name and class number, which would also make it easier for you since you could ensure at the beginning of class that any code you get turned in has the student’s name on it and any other relevant frontmatter. The other features that I think are not necessarily intuitive to brand new users but are extremely useful and will make the difference between a capable user and a befuddled one include multiple cursors, the Command Palette, the Keybinding Resolver, and the ability to configure individual package settings.
One thing I’d show off in front of the whole class (assuming you have a projector) is the output in the dev tools console of the method