I’ve just taken a quick look.
I’ve not used Empire before but here are my assumptions.
1) By default your homepage is pre set and includes a slider
2 ) You can’t add sliders to other pages – unless you use a plugin like wooslider.
3) To add new content below your slider you do via pages. At the moment your content under the slider is coming from the Page ‘smart witness’. This is set in Empire/Theme Options/Layout settings.
Let me know if that makes sense :)