Answer:
The entrance sounds unpretentious and simple. This is done to unleash a feeling that keeping a notebook is a casual and peaceful activity, allowing the reader to believe that he is capable of it.
Step-by-step explanation:
Didion wants to encourage the reader to maintain the habit of writing on a notebook. For that, she needs to show that this habit is easy, fast, profitable and that anyone is able to do it without much effort, being able, then, to benefit from all the benefits that this habit provides.
To highlight this, she starts the article with a real notebook entry. This entry is simple, unpretentious, but complete and specific, but does not present difficulties or great requirements.