Flash search app will detect all the themes in your store and let you select a theme to implement the filter & search features. We recommend you duplicate your theme before adding the app features to your live one. This gives you a chance to test how the app features works without affecting your live store. The instructions to setup layout with Flash Search features greatly depend on the version of the theme you are using. We have two cases with Normal Theme and Shopify Online Store 2.0 Theme. Then, make sure to select the instructions that apply to your version. Using instructions that do not apply to your version will not work.