This demo site page shows how to use Site Search 360 with a grid layout. 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 */
   },
   results: {
      embedConfig: {
         contentBlock: '.example__page-content-block'  /* Replace with the css selector of the DOM element you want to use */
      }
   },
   layout: {
      mobile: {
         type: 'grid'
      },
      desktop: {
         type: 'grid'
      }
   }
};