move the mouse to the header you want to customize and then click on the header to call the edit menu.
Click on the button "Edit Area Design" which is displayed under the text "Layout Area - Header 1". Depending on which header you want to edit, you will also find Header 2 or Header 3.
It open the dialog for editing the header area.
In the first row of the dialog you will find sliders with which you can set the width of the overall layout, the Höhe of the header and abst
In the second row the background is set. The header image is a background image.
click on the pen next to the trash to edit the background image. Note that you can include up to 10 wallpapers with a purchase version and these will then be displayed as a slideshow. After you have clicked on the pen, the dialog with which you can insert pictures opens. If images are already stored, they are displayed with a preview image. If you move the mouse over such a preview image, a wastebasket appears. You can use it to paint a picture. Or click on the image to move it to another position with the mouse pressed. This determines the order in which the images are displayed in the slideshow. If there is no image, use the image selector at the top of the dialog to select an image. Then click the "Apply" button to transfer the image to the design and thus to the header.
Now you can use the slider to adjust the height of the header and use the options in the second row to determine how the image should be displayed. The display options are described here.
Save your changes in the top right corner of the design editor and then exit the editor.