Mega menu and Slider help

Hello,

I have followed your guides for the slider (https://xtemos.com/docs-topic/create-mega-menu/), but my theme doesn’t have a backend editor, which was mentioned at 1 minute 40 seconds. How can I create a mega menu?

I have also followed your guide for the slider on https://xtemos.com/docs-topic/how-to-create-a-slider/. I can’t figure how to change the default background image.

Otherwise everything else is fine with the site. Can you please help with the above.