Readme update to include command line arg info.

Author: mkachk

docsource/content.md

@@ -20,6 +20,15 @@ Before running, configure **`DigicertMetadataSync.dll.config`** and **`manualfie
 
 ## Settings
 
+### Command Line Arguments
+One of these two arguments needs to be used for the tool to run.
+
+- **"kftodc"**
+Syncronizes the contents of custom fields listed in manualfields.json from Keyfactor to DigiCert. If the fields in manualfields.json do not exist in Keyfactor or DigiCert, they are created first. Example: `.\DigicertMetadataSync.exe kftodc`
+
+- **"dctokf"**
+Syncronizes the contents of both custom and non-custom fields from DigiCert to Keyfactor. The fields are listed in manualfields.json, and are created if necessary. Example: `.\DigicertMetadataSync.exe dctokf`
+
 ### `DigicertMetadataSync.dll.config` keys
 - **`DigicertAPIKey`**  
   Your DigiCert API Key with **API key restrictions** set to **Orders, Domains and Organizations".