In a genesis powered site if you want to add a small piece of content just after the main post content you need to add the following code in functions.php file.
Genesis Sample is the best starter child theme for customization and its FREE. Here we shall describe steps to make a single column, responsive, minimal theme.
From the GtMetrix and Google Page Speed result, you can notice that the jquery is loaded at the time of site loading resulting increased initial loading time.
To customize Genesis archive page, you need to create a file named page_archive.php and upload it to the theme folder. Then you can edit the file as per your requirement.