Try it in english:

Hello everybody,
I’m still brand new to WordPress and I’m just starting.
Now I have a problem:
We installed the SEO plugin Yoast today, so far so good.
Since then we have received a Canoncial link for our homepage
“<link rel =” canonical “href =” https://www.superpos.de/superpos/ ”
displayed when the search engine optimizer gripe pages
With the settings in the Enfold tab you can say which page the homepage should be, I guess it has something to do with it. However, this page can only be seen on the homepage and nowhere else.
Can someone tell me what I did wrong where?

Thank you in advance.

best regards
Sarah