Update doc

Author: wchen-r7

documentation/modules/exploit/windows/fileformat/office_word_macro.md

@@ -37,6 +37,11 @@ Specifically, this module was tested specifically against:
 
 ## Demo
 
+In this example, first we generate the malicious docm exploit, and then we set up a
+windows/meterpreter/reverse_tcp handler to receive a session. Next, we copy the docm
+exploit to a Windows machine with Office 2013 installed, when the document runs the
+macro, we get a session:
+
 ![macro_demo](https://cloud.githubusercontent.com/assets/1170914/22602348/751f9d66-ea08-11e6-92ce-4e52f88aaebf.gif)
 
 ## Modification