Let's break it down:
* donde: where
* lees: you read (present tense, informal "you")
* los libros: the books
Therefore, the entire sentence asks about the location where someone reads their books.
Let's break it down:
* donde: where
* lees: you read (present tense, informal "you")
* los libros: the books
Therefore, the entire sentence asks about the location where someone reads their books.