Adding content to slider

Checked the theme tutorial (Deep Focus by Elegant Themes) and couldn’t find anything about adding content to a slider. The original designer added my content to two of the four sliders, but not the other two. No longer working with him.

Present URL: https://www.eiorn.com/greg

How do I add new content? When I go to the page and add it as a post, it shows up below the overlay statement (slug?) over the slider picture. I want it to show up as a post after you click on the “Read More” button. When I click on the “Read More” now it just pulls up “No Results Found”.I’d appreciate any help you can give me.

Thanks.