Hi, @John,
To add XML file: Right-click your project in Solution Explorer, choose "Add" > "Existing Item," and select your XML file.
To add XSD file (if needed) use the same method above.
You can edit the XML file by double-clicking it in Solution Explorer.
To associate XSD with XML, you can add this line to your XML file:
<?xml version="1.0" encoding="utf-8"?>
<YourRootElement xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="YourSchema.xsd">
Visual Studio will validate and provide IntelliSense based on the XSD.
You can then save your files.