Invoke Transform F9 in an XML or XSL document to perform the transformation (this uses MSXML XSLT). If the stylesheet is specified in the XML file you can just press F9 and it will begin immediately. Specify the XSL file as follows:

<?xml-stylesheet href="file.xsl" type="text/xsl"?>

If the XSL file is not specified, you must have both the XML and XSL documents open in the editor. When you invoke the Transform, you will be prompted with a list of open documents to select the other document. So if you press F9 from the XML document it will prompt you for the stylesheet, and if you press F9 from the stylesheet, it will prompt you for the XML to transform.

Like MSXML Validate Alt+F7, the Transform function uses the Windows MSXML component on your machine.