Vimeo Displayed on Blog Page?

I had this working a while ago but then I added a function to my functions.php file and it seemed to break my whole site. I’ve got it mostly up and running again with one exception…

I just want to display a vimeo video on my main blog page just like a thumbnail for the post. I have the Auto Post Thumbnail plugin installed and that’s how I thought it was working before, but it only seems to work on images now. An example would be https://www.greyscalegorilla.com, how you can see and play each post’s videos from the main blog page, and also in the post.

Probably a pretty easy fix, but I’ve tried all I can think of to get this working again with no luck ??

Thanks!