Hi Julie….first up, I actually uploaded a new version of Encounters which helps with some of the mobile styling on elements such as logo and menu to be centered on smaller screens. Anyway, to control/manage where widgets are shown, the plugin called Dynamic Widgets is what I use, which I have a video tutorial for that one.
https://www.styledthemes.com/encounters-theme-setup/133-how-to-publish-widgets-to-select-pages
So because the showcase and banner uses widgets as they are widget positions, the video will help you with this one.