No “feature image” tab in Post Editor

I am new to WordPress–just moved over from Blogger. I am having problems with the feature images displaying properly. I was working on a post in the post editor and accidentally made the feature image disappear. Now I can’t figure out how to get the feature image back.

I found some documentation about the post editor and it appears there should be a “feature image” tab that I can use to activate the image. However, there is no feature image tab in my post editor.

“Featured Images” is checked under screen options, but that doesn’t seem to do anything.

I was reading some forum posts that said sometimes things like this are related to the theme being used. I am trying to work with the Hueman theme. Is my problem possibly related to that?

The page I need help with: [log in to see the link]