Children often begin reading by retelling their favourite story over and over - they probably have a favourite book that you have read a hundred times, so now they can tell it word for word. . .and probably even know when you skip a few words! This process can seem tiresome to adults, but it is developing children's vocabulary and story language, and helping them to learn the sequence of stories with a beginning, middle and end.
It also teaches them to look at the pictures for clues to help them tell the story, and this is a strategy we teach to help them when they are reading words in books. Things you do naturally, such as asking your child questions about the story as you read it, predicting endings and so on, all form part of the reading journey too, as it makes children think about what they are listening to. Later on, this 'comprehension' is important to check children's understanding of what they have just read.