How did Alice first find Wonderland?

Alice's Adventures in Wonderland (also known as Alice in Wonderland) is an 1865 English children's novel by Lewis Carroll, a mathematics don at the University of Oxford. It details the story of a girl named Alice who falls through a rabbit hole into a fantasy world of anthropomorphic creatures. It is seen as an example of the literary nonsense genre. It received positive reviews upon release and is now one of the best-known works of Victorian literature; its narrative, structure, characters and imagery have had a widespread influence on popular culture and literature, especially in the fantasy genre.

Source: Wikipedia