How to add text and button link on header image like in the theme demo

Hi,

I am trying to recreate the main look of the theme demo version. In that version the header image has text on it with a clickable link “Great Food, Great Prices” and a description right under.. How do I add this to my site? Also How do I add these side arrows to my header images. At the moment they are just switching between each other each time I refresh the page.