Include/Exclude Posts

I just got Version 5.12.25. I can’t get the Include/Exclude feature which is on the bottom of each post to work. I am displaying the related posts through a widget in a sidebar. Do I have to have the settings of the widget set to something in particular for it only to show the posts that I have tabbed on the ‘Include’ list. Also if my post number is set to ‘4’ and there is only ‘2’ included posts for a said post then how does that work?

https://www.ads-software.com/plugins/yuzo-related-post/