BuddyPress.org

Likely if the plugin is called ‘single random post’ then you would place some form of template tag in one of the post loop pages i.e index.php or single.php however you are asking a question about a plugin on another plugins support site, I assume this isn’t a BuddyPress specific plugin but a WP one? If the plugin instructions are not clear then it might be best to see if the authors can answer specific questions.