Directory for Add on Blogs is it possible

For my Supporters is it possible to use the directory Plugin for add on Blogs and if Yes
there is instructions to edit the single.php template it says
19. Open up single.php file contained dp-theme folder of the Directory plugin using your code-editing program.
20. Add the embed code inside your WordPress loop where you want your new custom fields t to appear.
21. Save your new version of single.php and upload to your dp-default folder inside directory folder in /wp-content/plugins/
If its compatible where would the add on blog upload the single.php file? whats the procedure to do it?