featured post

Hi, I would like to display featured posts in the category list.
I installed a plugin called: Featured Post
and it says that i have to add the following code before the loop starts:

<?php query_posts($query_string."&featured=yes"); ?>

can you pls help me to detect where to add this code? I cannot find it…
or… if you have this functionality available in the lcp plugin pls let me know
Thanks
Bye

https://wordpress.org/plugins/list-category-posts/