Your username is linked to a blogspot blog. We need a link to the free hosted WordPress.com blog that your purchased the custom design upgrade for starting with http://
Please replace that blog link with it. Here’s how to link your WordPress.com username to your blog in your WordPress.com blog Dashboard -> Users -> Personal Settings -> then scroll down to Account Details. Then scroll down to where it says ‘Website‘ select the URL for your primary wordpress.com blog and then save changes.
In Manifest the author byline does not show up on the main page where all the posts are listed, but does show up on the single post pages you get to after clicking on a post title. You can verify that on the theme demo: http://manifestdemo.wordpress.com/