How does the audience learn from the background story of Miranda and prospero

In The Tempest, by William Shakespeare, we are told of the background story of Miranda and Prospero by Prospero himself. Upon seeing that Miranda is upset at the shipwreck that he caused, Prospero tries to calm her down. He also tries to prepare her for the people she is going to encounter. He decides it is finally time to tell her the story of how they came to be on the island and also reveals to her that she is the Princess of Milan.