Doesn't work?

Not sure, I could be doing something wrong. I'm on Sketch 3.4. These are the steps I took:
- Created a new sketch file
- Added new artboard (Tablet 7" portrait)
- Created a shape, renamed it 'block'.
- Duplicated shape twice, so there are 3 in total with identical names.
- Used "Set Page's Stylesheet" command for plugin and linked a blank stylesheet 'styles.css'.
- Opened styles.css in text wrangler and added some selectors for the block elements.
- Saved stylesheet.
- Saved sketch file to same directory as stylesheet with same name.
- Also tried using "Layout Layers" command.

Nothing happens. Screenshot attached.