add note on cloud9 opening files

README.md

@@ -35,7 +35,7 @@ If you haven't already, fork and clone this lesson into your local environment.
 > your fork of this lab's repository.
 
 Navigate into the newly createtd directory in the terminal, then run `code .` to open the files
-in Visual Studio Code. (If you are using a different text editor, the command will be different.)
+in Visual Studio Code. (If you are using a different text editor, the command will be different. For the AWS Cloud9 IDE, for example, you must click on the file in the left navigation to open it)
 Finally, run `bundle` to install the lab's dependencies.
 
 > **Note:** This lab's test use Ruby, so the commands we'll use are different than what you've