To bring up all documents containing a particular word or phrase type the word or phrase into the Project Search box
You can open the disclosure triangle beside the magnifier icon to narrow your search to your chosen criteria.
You can aslo save your search word or phrase as a collection. In this case I would be creating a collection of documents containing the word 'witch'. Then I could go through all scenes that mention the witch and work on them together without the distraction of the surrounding scenes.
A temporary replacement display will appear in the Binder with a list of all the documents in your project that have the word or phrase in them.
If you open any of the listed documents in this search results display in the Binder window, you will see all instances of your word highlighted in the document in your Editor.
If you only need this information temporarily delete the word from your Project Search box when you are done and the regular Binder display will reappear in the Binder window.
By default, Scrivener saves your most recent search as a collection until you type a new search into the Project Search box. So even if you don't save your search you can temporarily access it by clicking on Collections in the toolbar and opening up the Search Results tab.
Click on Collections in the toolbar and choose the Search Results tab.
To return to the Binder display from within the Collections display click on the ghosted out Binder tab.