clarify the debug scenario

The original text was ambiguous as the user just added a Debug node and there is a sidebar for that node called "debug". There also, it turns out, is a Debug sidebar (vs the Info sidebar).  I was injecting and injecting and nothing was happening...

The doc might be a bit better if it included the actual icon in the text but I did not see that in the `images` folder.

Author: jeffmcaffer

docs/tutorials/first-flow.md

@@ -54,7 +54,7 @@ server.
 
 Click the Deploy button.
 
-With the Debug sidebar tab selected, click the Inject button. You should see
+With the Debug sidebar tab selected (click the bug icon at the top right), click the Inject button. You should see
 numbers appear in the sidebar. By default, the Inject node uses the number of
 milliseconds since January 1st, 1970 as its payload.