In the 'Logo Carousel' element, you can add logotypes that will be listed in a slide.
The Logo Carousel can be selected below the tab 'Content elements' when creating a new element. (1.9.1)
In the 'General' tab you can see that the content element type 'Logo Carousel' is selected (1).
The element uses the regular header field (2). (1.9.2)
For this type of element you need to add images. You can do this by moving to the 'Logos' tab and clicking 'Add image' - there you can select all the images you want to have in the logo carousel. (1.9.3)