Content in Template?

Hi all,
i try to build a static page in twenty twenty four.
No matter what i do, if i set any page to home (Startseite) it always shows me the template: Startseite and not my own content. I changed the template, when editing the page in the right sidebar, on another one i created. Doesn´t work.
Help forums and videos say: go to options / read / show: site xyz (did that) – seems easy but doesn´t work. That was the reason i created another template, that looked like my content page i want to have as front page, but all it shows is the Startseite Template that comes with 2024.

Do i have to put my content into the template? (Internet says no, but i cannot find another solution)

Thanks in advance!
Kriss