Insert a photo above the slider

I’m sorry but support here is provided only for themes that is downloaded from www.remarpro.com
You are using a commercial/non free theme so I suggest you to ask for support from where you first got the theme.

Anyway, I can tell you that creating a child theme is a good start for you. and I wouldn’t suggest modifying the original theme files as you will lose all the customization you make as soon as you update your theme.