If you want the author bio for each post to display in the Twenty Thirteen theme you must have a multi-author site. Therefore You mus either get someone to write a post for you or create a dummy author and publish a post from them. So go to users and create a new author, then log in and publish a post from them. It’s a little annoying that this is the default setting with this theme, but that’s the way it is. There is a post about this in the WordPress forums here. The extra annoying part is that the post has to be published and not private. However, this is not a problem if you have other authors. You must also remember to fill in the author description on the profile page in the admin area.
As this ite is using a Twenty Thirteen child theme, this post and author were created soley for this purpose.