Adding or changing elements independently to my responsive Design

You do have a Header Element ( in Appearance > Elements ) that is merging the Site header and content that i don't think is required.

OK, how can I change that? I want the navigation to be under my Header Picture on every page and for Desctop Tablet and eventually also for mobile.

Hi Dennis,

To clarify: Do you want this order of layout?
https://share.getcloudapp.com/8LuppRDq

If yes, you'll have to remove the merge as David mentioned.

You can do that through Appearance > Elements and look for Header elements that may be applied to the "Front page" or "Entire site".

You then go to its "Site Header" tab and set the "Merge with content" dropdown to "No Merge".
https://share.getcloudapp.com/o0uZZrX0

You then add this CSS:

body {
    display:  flex;
    flex-direction: column;
    flex-wrap: nowrap;
}

.page-hero {
    order: -1;
}

Here's how to add CSS:
https://docs.generatepress.com/article/adding-css/

Yes, this is exactly what I want to have.
I tried it and it worked as long as I stay in the customizer, but as soon as I leave, it switches to the top again. I already deleted all previously added CSS, so I don't know, what other options I have.

I tried it and it worked as long as I stay in the customizer, but as soon as I leave, it switches to the top again. I already deleted all previously added CSS, so I don’t know, what other options I have.

You may be seeing a cached version of the front-end if you're already seeing it working through the customizer.

Consider clearing all kinds of cache(browser cache, CDN, page cache, plugin cache) and check if it finally applies. :D

I worked it out.

Thanks for helping me ;-)

No problem. Glad you got it sorted. Thanks for letting us know. :D