Making small changes directly to the XML is not hard. Any text editor such as Notepad or Wordpad can be used. Make sure that all saves are in text format. Be careful with quotation marks and the ending characters. The indentation is used solely for readability.
Here is an example for XML code
<unitPlacement unitType="infantry" territory="Russia" quantity="3" owner="Russians"/>
The entire line here is an element. unitType is an attribute. Attributes can be in any order.