User blog comment:BlueRaptor 01/Main Page Slider/@comment-44807868-20200911144339

The UCP visual editor doesn't have option for adding a slider for some reason, so you'll have to switch to source mode and add the slider through it instead. Have a look at Help:Galleries, Slideshows, and Sliders/wikitext if you don't know how to add a slider in source mode.