Generatepress Peak template

Good afternoon,

We have a question we imported the template: Peak from the site library.
Now we wonder, where is it possible to change the layout of the pages and the blog?
There is now a black box above each new page, we would like to give it a different color.
Within this blackbox it's possible to set an featured image.
But we cannot find the setting of this anywhere, do you know where we can find it?

Thanks in advance.