This update (Sep 28, 2018) of the tool no longer includes the Excel add-in, regarded as too clumsy to activate on recent Excel versions (beginning with Excel 2013 due to Microsoft willing to favor their own Javascript based add-ins instead of COM add-ins), and perhaps too "in your face" with the right hand side navigation pane being there until you hide it.

The standalone version of the search tool is now your primary entry point for performing searches.