Replace header search with a plugin search?

I’m trying to get an ajax/realtime search to replace the out-of-the-box one on the topbar of the theme.

The search plugin gives shortcode and a php snippet to include in templates. I wondered if I actually need to add this into the template (if so, where?), or whether it’s possible to use the custom css or something else to do the same thing?

Thanks,

Adam

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