Some clarifiction is needed

On the Multithemes page for the Gamma theme it says to “Open the Theme content and all images ( contents/images/editable_images/image_…jpg).” While it has a small image with this instruction, the image is out of context so I have not idea of how to get to it. I.e. how do I “Open the Theme content and all images”? Can someone help with this?

Simply right-click on the theme in the theme-drawer and select “Show Contents”: