Changing the header look on a communication site

[MSCom]

Hi there,

I am trying to change the header look on my newly created communication site. the result should look like in the example here (color background and sub-menus):

https://techcommunity.microsoft.com...ning-and-building-a-modern-digital/ba-p/88638

the manual to do so I found:

https://support.office.com/en-us/ar...int-site-06bbadc3-6b04-4a60-9d14-894f6a170818

However, on my site, if I go to "Change the look" the only thing I can change is the color layout. Neither "Header" nor "Navigation" is available to choose from. I have full admin rights on our sharepoint site / farm, so i doubt its a permission issue.

Now, how do I get to change the header as in the example?

cheers for any help!