First, on your HubSpot page:
Place a "Rich text" section anywhere on the page
Select the section and go to Advanced -> Source Code
Place this code (replace EVENT_ID_GOES_HERE with the actual event id)
<div id="embed" style="width: 100%; position: relative; z-index: 1;"> </div>
<script type="text/javascript">
setTimeout(function () {
var url = document.location.search;
var divEl = document.getElementById("embed");
divEl.innerHTML = '<iframe title="Sequel event" width="100%" height="80vh" src="https://embed.sequel.io/event/EVENT_ID_GOES_HERE' + url + '" frameborder="0" allow="camera *; microphone *; autoplay; display-capture *" allowfullscreen style="height: 80vh; border-radius: 12px; border: 1px solid #dbdfec; box-shadow: 3px 3px 10px 0 rgb(20 20 43 / 4%); width:100%"></iframe>';
}, 1000);
</script>NOTE: Nothing will show up in the editor. You have to Preview or Publish to test.
That's it! Save and refresh your page, and you'll be able to start hosting your experience right away.