The service is slowly rolling the feature out to the public channel to be able to catch any early issues that may arise before they make it to most users' devices. Ivasyuk added that the company hopes to eventually be able to use the normal beta channel to test new features, so you wouldn't have to install a separate app. For now, you'll just have to wait for the feature to make it to the stable version of the manager on your device. That is, unless you're still waiting for Oreo itself to hit your phone.