Imagine a clock in a scene. Is it running or stopped?
For action and dialogue, it's running; for descriptions of setting and character, it's stopped. Let's call this distinction "action" versus "description/setting" (which I sometimes call just "description" or "setting").
It's natural and easy to start a story with description/setting, which is to say, describing the world as it is before any action. "Once upon a time there was..."
So olden books usually (almost always?) begin with setting. From 1900:
Dorothy lived in the midst of the great Kansas prairies, with Uncle Henry, who was a farmer, and Aunt Em, who was the farmer's wife. Their house was small, for the lumber to build it had to be carried by wagon many miles. There were four walls, a floor and a roof, which made one room; and this room contained... (The Wonderful Wizard of Oz, Baum)
And so it continues for 500 words until the first action.
It's just a curiosity but it's an interesting curiosity: Ater a start of setting, the transition to action is often stated. After a page of setting:
When Mr. and Mrs. Dursley woke up on the dull, gray Tuesday our story starts, there was nothing about the cloudy sky outside to... (Harry Potter and the Sorcerer's Stone, Rawlings)
After three (paperback) pages of mostly character description:
I'm not nearly so exotic, having Austrian and Danish ancestors who left me with wimpy blond hair and a body that looks more athletic than it actually is.
It was Tuesday morning...
(Wicked Appetite, Evanovich)
And from the example up top:
Today, however, they were not playing. Uncle Henry sat upon the doorstep and looked anxiously at the sky...