Theme Horse

Hi caousou31,
Do you like to add header image to display random while clicking on next page or you want as in our demo site?

For your header image go to dashboard -> appearance -> header and upload the header image and select the image to randomize.
View this screen shot
http://awesomescreenshot.com/01045qdl60

If you want to display slider as in our demo site then you may just follow the theme instruction or we have already replied in forum. So you may search it in forum too.
https://www.themehorse.com/theme-instruction/attitude/

Thank you!