How to add a button to the listings page?

Hi,

I want to have a page on my site that serves as a directory of book cover designers.

This is the listings page: http://thebookcoverdesigner.com/listings/

The problem I'm having is, how can I add a 'Add Listing' button to this page so designers can add their listing to it? I was going to edit the page and add a button shortcode to it but apparently the page is virtual and cannot be edited in this way.

Thanks in advance,
Charlie