Zack 990 theme – how do I modify the post view

I am using https://andreamignolo.com/zack-990 theme on my blog: https://www.noworkday.com and wanted to modify the post view, but can’t as there is now single post file in the theme, or I just can’t find it.

Wanted to add twitter and FB like buttons to the end of the post. Any ideas how can I do it with this theme?

thanks,