How to enable ChromeOS Mode？

Tutorial video: 

I. Steps to Set  (If you use printer on Chromebook, you must enable ChromeOS Mode)

1. Ensure the printer is powered on and loaded with label paper (matching the correct paper type).

2. Press and hold the function button (the only button on the top of the printer):

   • Hold for about 9 seconds until you hear three beeps, then release immediately.