Flesh out the README a bit.

Author: jclarke-csco

eem_configdiff_to_spark/README.md

@@ -1,12 +1,25 @@
 # EEM: Config Diff to Cisco Spark
 
-An EEM+Python policy that pushes config change diffs to Spark
+An EEM+Python policy that pushes config change diffs to Spark.
 
 ![](spark_notice1.png)
 
 ## Setup
 
-This script requires the following EEM environment variables to be defined:
+This script requires the IOS-XE _guestshell_ feature.  To enable guestshell, configure:
+
+   ```
+   iox
+   ```
+
+Then type the following in `EXEC` mode:
+
+   ```
+   guestshell enable
+   ```
+
+Next, define the following EEM environment. Be sure *NOT* to put quotes around the variable
+values:
 
 * `spark_token` : Bearer token for your Spark user/bot
 * `spark_room`  : Spark room name to which messages will be sent
@@ -15,6 +28,20 @@ This script requires the following EEM environment variables to be defined:
     event manager environment spark_token Bearer 1234abd...
     event manager environment spark_room Network Operators
     ```
-    
+Once the environment variables have been defined, copy the script to the EEM user policy
+directory.  If you have not defined an EEM user policy directory yet, a good choice is
+to create a directory called `flash:/policies` in which to store EEM policies.  Once
+the directory has been created, configure:
+
+   ```
+   event manager directory user policy flash:policies
+   ```
+
+Once your policy has been copied into that directory, register it with the following
+command:
+
+   ```
+   event manager policy sl_config_diff_to_spark.py
+   ```
 
-    
+Once configuration changes start to happen, check your specified Spark room for updates.