I really need to put this in the plugin's FAQ because this is one of the most frequently asked questions I see.
[wp_biographia] shortcode is what you need to make a contributors page. See the plugin's Shortcode Usage and Support section, either on the WordPress plugin repository (http://wordpress.org/extend/plugins/wp-biographia/other_notes/) or on the plugin's home page (http://www.vicchi.org/codeage/wp-biographia/4-shortcode-usage-and-support/).
author attribute for the shortcode is the solution. Using the shortcode as
[wp_biographia author="*"] will produce Biography Boxes for all users on your site.
To copy-and-paste from the documentation ...
If the author attribute is omitted, which is the default, the shortcode assumes it’s being used within the WordPress Loop and will display the Biography Box once for the current post’s, page’s or custom post type’s author.
Specifying a user’s login name as the author attribute overrides this behaviour and allows multi-user sites to use the plugin to create a contributors page, where you use the shortcode as
[wp_biographia author="login-name"] once for each of your site’s authors that you want to appear, replacing
"login-name" with a valid login name for one of your authors.
You call also use the author attribute in wildcard mode, specifying the author’s login name as
[wp_biographia author="*"]; this will then loop over all of the authors that have logins on your site, displaying the Biography Box once for each author, ordered alphabetically by login name.