I do not understand to position the picture of the header to the left side:

http://www.pts.deutschland-debatte.de/

And additionally the hight of the header area. Where to change?

Could you please help me?

Tx in advance

You need to check through the various settings and start to get familiar with them. There are over 250 settings and sometimes there are several ways to accomplish what you want.

The theme setting you currently have are from the theme style that is installed by default when you install Atahualpa to show you some of what it can do. You change the style as described in the FAQ thread. Specifically this post.

You can alternatively make changes in the CSS of your site in ATO>Add HTML/CSS Inserts>CSS Inserts and other "Style" sections of the theme options.

For example to change the height of the header image you go to ATO>Header Image or you could go to ATO>Style & edit Header Area and change the logo area styling.

As you can see there is often no one way to do something.

Sorry, I'm not talking about 250 settings. I'm simply talking about organizing the header. Have you checked the link? Have you seen, that the image of the header is centered? How to bring this to the left side?

Another item:

I made a web page for a French Professor: http://www.resolution-individuelle.eu/fr/ - Atahualpa 3.4.9

There everything worked well so I exported settings. As I saw in Atahualpa 3.5.3 "Export the current Atahualpa settings and download them as a text file. This text file can be imported into this or another Atahualpa 3.4.7+ installation" so I thought I could use the setting of http://www.resolution-individuelle.eu/fr/ for http://www.pts.deutschland-debatte.de/ - but it did not work as you could see.

your header image is not showing up (at least when I looked) is is 'atahualpa353/images/header/header blanc w pts.jpg' - having blank characters in a file name is not a good idea. You should change them to a dash or underscore.

The header image spans the header. If you want an image to be to one side or another, then you could make the image that way or use a widget instead of the %image in the header and put your image in it. then you could position the widget with CSS

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the import export code changed from 3.4.9 to 3.5.2 - this is from teh 3.5.2 notes:

Export/Import system now uses the JSON format instead of the serialized/base64_encode format used in 3.5.1
The reason for the change is that Wordpress.org won't list the base64_ version due to the malicious things often done with base64. Sorry I should have thought about that. base64 encoding the settings files seemed to be a quick fix for the issues many users had with the settings files.
Unfortunately this means that if you exported a settings file in 3.5.1 and want to import that in 3.5.2, you'd need to do some legwork: Download this zip file, extract it, rename the "uploadBASE64.php" to "upload.php" and replace the existing "upload.php" in Atahualpa 3.5.2 with it.
If you don't have old settings files that you want to import then you don't need to do the steps described above

This is one of 7 pictures I have. This one sized 1300 x 180 Pixel is blanc some others with picture. But you see there a blue text on that header blanc w pts.jpg "Wir arbeiten miteinander".

First is: I see this header blanc w pts.jpg twice
Second is: the picture does not start at the left side
Third is: copying the setting from http://www.resolution-individuelle.eu/fr/ - Atahualpa 3.4.9 into http://www.pts.deutschland-debatte.de/ does not work although it should work.

First: rename all images so there are no blanks in the names
Second: importing 3.4.9 to 3.5.3 - did you use the method described above?