Can't find query_posts

Hi guys
I’m terrible at wordpress. Ages ago I installed this plugin: https://www.ads-software.com/extend/plugins/select-featured-posts/installation/

It’s causing me loads of grief now and I just need to get rid of it. I’ve obviously copied the codes provided somewhere but I can’t find where. I have deactivated the plugin but the features posts still appear.

https://www.sunshinemachine.org

Any and all help is a huge help!
Thanks