Sorry for the late reply on this.
After you install the plugin you need to go to Appearance > Widgets and include the widget in a sidebar.
Note that the widget will not appear on listing pages as this does not allow the plugin to determine posts related to which one should be shown.
Rather this only works on a blogposts’ details page (you can also use this on other custom post types).
You can also use the [magadanski-similar-posts] shortcode within the contents of a post to show the related ones to it.
I hope that was helpful. Let me know if you have any other questions.
