This is where the plugin Dynamic Widgets come into play. By default, WordPress loads a widget on all pages that contains that widget position. So to select where a widget is seen, there’s a few options:
1. Dynamic Widgets plugin
2. JetPack with it’s Widget Visibility feature (if you have jetpack installed)
3. Widget Logic plugin (but I still prefer the first or second option above.
I have a tutorial for Dynamic Widgets for Encounters, but the video audio is not as good as it should be. You can check out the one for Celestial Reloaded as a reference: https://www.styledthemes.com/celestial-reloaded-setup/82-how-to-show-any-widget-on-specific-pages