my word press installation suggests to use Plugin “Lingotek” for automatic translation. But I fear, it’s not for free 🙁
Polylang is only for creating pages in different languages with the possibility to switch to the “same” page in another language (for example “About us” > “Über uns” instead of > Startseite (de)). But you need to fill in the translated texts by yourself. As translation tool I suggest deepl.com. It translates great.
I used “Duplicate Page”, but the EN start page needs to be created with polylang. You need to click on the “+” in the “english” column and it needs to build it again (in my case with “yootheme page builder”) from zero 🙁
Now I found the reason for the problem: the EN page was not created by Polylang, insteasd of it with “Duplicate page” Plugin. For all other pages it’s not a problem, because the link to other language links to start page. But Start page MUST be created using polylang.