Swiftype Search code for Word Press Plugin

I would like to stylize the search using word press plugin so i prefer to use the swiftype search code but i’m getting blank results

<form>                                            
    <input type="text" id="st-search-input" class="st-search-input search-field" />
    <button type="submit">Submit</button>
</form>

does this apply when using a WordPress Plugin?

Solid question! For stylizing the look of the search input and results you’ll need to customize your theme directly, as the hooks included in your question above are specific to using the JavaScript embed code over the Swiftype WP plug-in.

This is a bit of an older WP forum thread, but the concept and approach of customizing the standard WP search widget should hold true: Customizing Search Widget | WordPress.org

When using our WP plug-in, Swiftype will take over the search behavior behind the scenes, while the look of the input and results page is dictated by your theme.