Karen tries to play audiobook files on her phone but they don't play in the proper order. Leo says that's likely because the player isn't very smart, and can't read the metadata. It's only looking at a file name. So she may need to number those media files in order so it will read them back properly. A better player will do.
Leo recommends LibriVox. It's an open source player for spoken words. Here's a list of other alternative Android apps that will do this.