Clarify README per #10081

examples/standalone-preview/README.md

@@ -14,7 +14,9 @@ To view the stories in the storybook UI:
 
 ```
 cd ../official-storybook
-yarn storybook --preview-url=http://localhost:1337/iframe.html
+npm storybook -- --preview-url=http://localhost:1337/iframe.html # or yarn
 ```
 
 This runs the Storybook dev server, but instead of showing `official-storybook`'s stories, it attaches to the `parcel` dev server, lists its stories in the navigation, and shows its stories in the preview iframe.
+
+> NOTE: This can be run from any working storybook, not just `official-storybook`!