IL Print is currently optimized for DYMO printers, however, some users have had success with setting up their Zebra printers!
Next, you'll want to set up your Zebra Print settings to match your label size using the Options tab in your Printing Preferences:
The orientation should be portrait.
If you're running into label quality issues, try clicking on the 'Dithering' tab, and changing the setting to "None."
Before continuing, make sure that you are able to scan your labels.