Look away from the page and summarize for me what you know so far. Try to do it in one or two sentences.
What are you curious about?
Where do you think the story is headed?
Whatever you answered, that’s what Chekhov now has to work with. He has, already, with this first page, caused certain expectations and questions to arise. You’ll feel the rest of the story to be meaningful and coherent to the extent that it responds to these (or “takes them into account” or “exploits them”).
In the first pulse of a story, the writer is like a juggler, throwing bowling pins into the air. The rest of the story is the catching of those pins. At any point in the story, certain pins are up there and we can feel them. We’d better feel them. If not, the story has nothing out of which to make its meaning.
We might say that what’s happened over the course of this page is that the path the story is on has narrowed. The possibilities were infinite before you read it (it could have been about anything) but now it has become, slightly, “about” something.