enh: some text for organizing content

docs/tutorial/using-clairvoy.md

@@ -40,7 +40,12 @@ After pipeline completion:
 6. Choose the `Clairvoy App` from the list of Apps suggested by [brainlife.io](https://brainlife.io) and click submit. This should only take a minute or so to complete.
 7. When finished, the `Clairvoy App` output will state either: **This injury is at high risk of developing PPCS** in red letters, or **This injury is predicted to recover in under 28 days** in green letters.
 
-<div style="display: flex; align-items: center">
+
+## Demonstration
+
+**Here is a narrated video of running Clairvoy:**
+
+<div style="display: flex; justify-content: center">
 <iframe width="560" height="315" src="https://www.youtube.com/embed/TvVmsXITP_0?si=HBNc2dlK7mipZJY-" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
 </div>