How to silence my iphone 12 pro.

I just want to know how to silence my iphone 12 pro. This should be one of the easiest and intuitive things to do. I use the volume down button on the left side of my phone, and the image comes up on my screen that sound is off. Then I get a call with an audible ring. What exactly did I silence, then? I follow the instructions in Apple Support to the T, and (1)I don't have a ring/silence button as pictured, and (2) when I try changing it in settings, I click "ringtone" (instruction step#2) and there is no silence option. Only options to change the sound of my ringtone. Why is this so complicated?????