This demo site page shows how to use Site Search 360 in layover mode when search results are displayed in a popup on top of your pages. View the to check the configuration.

window.ss360Config = {
   siteId: 'spoonacular.com', /* Replace with your site id */
   searchBox: {
      selector: '#searchBox' /* Replace with the css selector of your search box */
   },
   suggestions: {
      dataPoints: {
         Calories: { position: 0, html: '<span>#Calories#</span>' },
         Cost: { position: 1, html: '<strong style="float:right;">#Cost#</strong>' }
      }
   }
};