Research plugin does not work

Hello,

i have a child theme of TwentyEleven in which the research plugin does not work. In the search.php file i can read this :

<?php
                        /* Include the Post-Format-specific template for the content.
                         * If you want to overload this in a child theme then include a file
                         * called content-___.php (where ___ is the Post Format name) and that will be used instead.
                         */
                        get_template_part( 'content', get_post_format() );
                    ?>

i do not understand what this note means… my three questions :
– how should i call the file (or i can give whatever name, for example content-search.php) ?
– what code should contain this new file ?
– do i have to change the code of the search.php file (here above) also and if yes, how ?