Author Bio and post covers in Demo

So this is the first time I have ever done anything like this (I’m not very computer savvy), but I still wanted to build it my own and not have the demo installed. However, I love the little author bio (“Hi!! I’m Emma!!” etc.) and the cover thing that recent posts have. I figured out how to make my own version of the “about me” (unless any knows the actual plugin name or CSS…), I cannot find in the Customize section where to where to make by archived post look like the demo. Help, pretty please ??
Thanks!!!

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