post_format example

in the index.php file there is this comment:

/* 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.
*/

Do you have a sample “content-___.php” as a starting point that would shows how to modify the layout of the posts?
When I google post format, results indicate changes needed to functions.php rather than a separate .php file.
thanks