I need help with the way saga cards work please.
"Saga Cards
Saga Cards are a new sub-type of Supports being introduced in Dominaria. When a Saga card enters the board, and at the beginning of your turn, read the current chapter and move to the next chapter. When you read the last chapter, destroy the Saga at the end of the turn. Whenever a Saga is reinforced, read the current chapter again without advancing to the next chapter."
I am not clear on how we ‘read the current chapter’ of the Saga Card. What takes place exactly?