Slideshow (Image Slider) on the home page was built using addon: Slideshow fullwidth. From its settings you can change images and Titles on it.

But to remove a dark layer from slide images you have to use custom CSS, all is based on background-color with transparency level (RGBA).
To reduce the dark layer 50% - use below CSS code:

.resort-slider .sppb-slideshow-fullwidth-item-bg::before
 {background-color: rgba(0,0,0,0.3);}

To fully turn it off, no dark layer - use below CSS code:

.resort-slider .sppb-slideshow-fullwidth-item-bg::before
 {background-color: transparent;}