I installed free relevanssi and successfully built this index per the instructions.
Problem: I don't see any change in behavior with the search results from the Word Press default search.
It sounds like Relevanssi should use the same search box (I am using the search box widget that came with my Studio Press Genesis/Agency theme.)
Further reading of the installation instructions say, "make sure your search results template uses the_excerpt() to display the entries, because the plugin creates the custom snippet by replacing the post excerpt." I can't find a template for search results for this theme.
I have been learning about Word Press but do not profess to be an expert. I would greatly appreciate help in making this plugin do what it sounds it should do.