Featured Slider and Image Size

Hi, I am trying to use the Featured Slider on my website. I want to have something very similar to the one that is presented in the Zubin pro demo: https://catchthemes.com/demo/zubin-pro/ However, when I insert an image (with the size 1920x1080 as recommended), it appears small and not full as the one in the demo. You can see it on the first slide: https://covid3d-umfasos.nl/ Am I forgetting to change some settings here? How should I proceed? Thank you! Kind regards, Camila