You can give your readers a couple of article options they should consider reading as they relate to the current post they just read.
When enabled, the thumbnails will automatically be generated for you. The posts that show up at the bottom of your articles will show related articles that share the same tags of a post.
Go to Appearance >> Customize >> Theme Options >>Post Settings
Look for the “Display Related Posts” setting under “Show or Hide Post Elements” options, then check the box for showing or uncheck to hide.
Once done, click “Save & Publish” at the top of the customizer window.
This theme includes a setting to set a crop size for your related posts thumbnails.
Go to the Customizer >> Theme Options >> Thumbnail Settings
Look for the related posts setting and check the box next to it, then click “Save & Publish“.
If a post does not have a featured image, a placeholder image will be used: