Offred can see almost nothing. That constraint is the book. You learn Gilead the way she does, in fragments, through a window and a shopping trip and whatever gets said when nobody dangerous is listening.
What struck me is how recent the before is. This is close to the present. A woman who had a bank account and a job a few years ago, remembering how fast the paperwork changed.
The Historical Notes at the end do something cruel and clever, handing the whole account to a future academic conference that treats it as a curiosity.
Read February 2022, immediately before The Testaments. The pair is worth doing together.