First add to functions.php:
add_filter( 'learn-press/override-templates', function(){ return true; } );
Second create the appropriate directory in your child theme that will override the plugin template location. Move a copy of the original template file into the directory you just created. As an Example, overriding learnpress addon bbpress link to the course forum.
/public_html/wp-content/themes/theme-name/learnpress/addons/bbpress/forum-link.php
Third, edit the file as desired.