Adding code for multiple authors by-line

Hello,

I would like to have some help placing the code for multiple authors as a by-line.

The plugin page tells to add the following code to the theme.

if(class_exists('WP_Post_Author')){ awpa_ma_multi_authors_list_post(); } else{ theme original code or function}

But is it also possible to add it with the plugin ‘WP Code’. If yes, how tot do this?

Thank you!