[Plugin: Related Posts for WordPress] How to specify related posts?

I can’t figure out how I’m supposed to specify related posts manually. On your website it seems there is some kind of panel (probably while editing a post?) but I can’t find it. It’s not listed under the “Options” drawer either.

So, how can I use this plugin?

Btw, I’m using WordPress with German localization. May be this is the problem?

https://www.ads-software.com/extend/plugins/microkids-related-posts/