scheduler.js

<script>
  // replace the current flow New_Guest_Appointment_Flow with the api name of your own flow
  // replace the current URL with your ownSite URL 
  
  $Lightning.use("runtime_appointmentbooking:lightningOutGuest", 
    () => {
    console.log('lightning out loaded');
      try {
        $Lightning.createComponent(
          "lightning:flow", // top-level component of your app 
          {},               // attributes to set on the component when created 
          "FlowContainer",  // the DOM location toinsert the component 
          function (component) {
            // API name of the Flow 
            component.startFlow("New_Guest_Appointment_Flow");
          }
        ); 
      } catch (e) {
        console.log(e); 
      } 
    }
    ,'https://live-demo-developer-edition.eu26.force.com'  // Site endpoint
  );
</script>