Add better description

md/01_raw_intro.md

@@ -43,7 +43,7 @@ Select the cell below and click <kbd>CTRL+ENTER</kbd> to run the cell. Once the
 ```
 
 <div class="alert alert-warning" role="alert" style="color: black;">
-    <details><summary style="cursor: pointer;"><strong>Refresh the browser window afterwards with <kbd>F5</kbd> and select <code>01_intro_env</code> in the top-right corner.</strong></summary>
+    <details><summary style="cursor: pointer;"><strong>Refresh the browser window afterwards with <kbd>F5</kbd> and select <code>01_intro_env</code> in the top-right corner. Wait until the <code>[*]</code> disappears.</strong></summary>
     Refresh the browser window afterwards with <kbd>F5</kbd>, so that the environment becomes available on the top-right dropdown list of kernels.
     </details>
 </div>