Our Marketplace Theme using a custom widget plugin called SwiperSlider. To set a new slider, please go to “Configuration / Widgets” and click “Configure”.
Also please disable Nivo Slider.
To add a new slider, please click “Add new”.
It opens a new pop-up window where you may add a new slide.
Add any image
Result would be visible on home page
Make sure the slider is placed at the widget zone "MainSlider"