Adjusting rear drum brakes on 2001 nissan sentra

Has anyone adjusted rear drum brakes on a Nissan Sentra? This car has a cam type mechanism which I have never seen. It is different from the conventional type which has a threaded rod and a star spinner wheel. any ideas? There is a rubber plug in the backing plate

All rear drum brakes are self-adjusting. This is done when the vehicle backs up and the brakes are applied. So while driving backwards, apply the brakes several times.

Tester