Did you use the import for the slider from the theme’s download to give you a starting point? It will basically give you a duplicate of the demo site’s slider where all you need to do is change the photos to your own? Also, to publish a widget to select pages, use the Dynamic Widgets plugin. I use this now in my newer themes and works wonders. For the slider, you would use a text widget and add the slider’s shortcode into it and then use the dynamic widgets plugin to only show it on the front page. The encounters video is not very good so check out the Celestial Reloaded video about publishing widgets to select pages https://www.styledthemes.com/celestial-reloaded-setup/157-how-to-show-any-widget-on-specific-pages
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