Hi there, please try adding the following css to either your style.css or custom css panel in the EBS admin panel from the WP admin area. Remember though to replace the images with your own which are large enough to fill the entire width of the page. I’d say at least 1500-2000px so you get most screen sizes covered.

#slider {
height: 400px;
left: 0;
margin: 0;
position: relative;
top: 0;
width: 100% !important;
z-index: 5;
}