This is the 9650th most frequent Turkish word.
anlatılan
"Anlatılan" means "that which is told or described."
In this context, "anlatılan" is used as an adjective meaning 'being told'. It describes the story ("hikaye") that is currently or has been narrated.
Anlatılan hikaye çok etkileyiciydi.
The story being told was very impactful.
Here, "anlatılanları" is the plural form and implies 'those things which are being (or were) described.' It is the direct object of the verb "dinledim" (listened).
Anlatılanları dikkatle dinledim.
I listened carefully to what was being described.
In this sentence, "anlatılanları" refers to the narrated or described contents of the book, acting as the object of the action "anlamak" (to understand).