"leave a comment" is missing

Hi! I am using a twenty ten child theme on https://www.stillesbunt.at. I wanted to add the “leave a comment” and a comment count with every post headline as it is in twenty eleven. Described in this topic https://www.ads-software.com/support/topic/adding-a-comment-count-and-comment-bubble-to-every-post-headline?replies=7

I used this tutorial: https://pastebin.com/BkPwSF1H

However, it did not work as you can see. Plus my “leave a comment” text – “Hinterlasse einen Kommentar” in German is missing now. It used to be under every blog post.

I traced all my steps back and undid the changes. But still nothing. As you can imagine, I am in a hurry to get the comment link back!

Help would be greatly appreciated!

thanks, Lilly