I would like to have tabs, but unsure how to add items. For example I would like to have reviews in a tab and videos in another.
You can create templates in elementor (a section). Using Templates > Section > add new.
Then in the templates list view you can copy the shortcode of the template and paste that in the tabs widget.
You can check out this YT tutorial to see the steps: https://www.youtube.com/watch?v=RgJYtcfDHQg