You have already added news items/gallery items in news custom post type/gallery post type.
So in the widget you just need to select the “post type” and set the carousel setting as per your needs and save it.
These all are the easiest widget to set since it doesn’t have any html elements .
However I am noticing that everything loads very well within wp admin. But when I try loading the website on another tab/browser some images don’t load. Examples include the logo, tab slider and responsive carousel. What could be the issue?