To create a narrated picture book on Story Creator start by inserting a picture as your book’s cover. To create a page just tap the “+” icon and import a picture, draw a picture, type some text, or do all three. After completing one or all three of those previous actions tap the microphone icon to record your narration. After making your recording you can quickly adjust it so that each word of text is highlighted to match the timing of your narration.
Via Andrea Zeitz