Galaxy S7 Oreo V8.0 - how do you turn volume down when screen is locked

[Spamdog]

Hi All

Just wondering if anyone knows how to turn down the volume in Oreo when the phone is locked. In Nougat it used to be a matter of pressing the power button until the options came up then pressing the lower side buttons (at which point the volume display would appear) and it would reduce in volume upon each successive press of the button. I've played around with the phone and googled this but can't see a way of doing it in Oreo.

Thanks