I guess I am a bit stupid, but I do not understand how to process xml in ConTeXt.
I started working through the contextXML-example.pdf from the Pragma site.
I tried to follow the example on page 8 which reads:
% here go style definitions
% and XML to TEX mappings
\starttext
\processXMLfilegrouped {filename.xml}
\stoptext

In TeXShop (working in the latest context-beta) I have the tex-input:

\def\Filenumber#1{[#1]}

<xsl:template match="dvd">
<xsl:apply-templates/>
</xsl:template>

<xsl:template match="dvd/filenumber">
<xsl:text>\Filenumber{</xsl:text>
<xsl:text>{\bf </xsl:text>
<xsl:apply-templates/>
<xsl:text>}</xsl:text>
<xsl:text>}</xsl:text>
</xsl:template>

\starttext
\processXMLfilegrouped {xml-input.xml}
\stoptext

and in file name.xml:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<dvd>
 <filenumber>D134</filenumber>
</dvd>

I get the obviously wrong result:

<xsl:template match="dvd"> <xsl:apply-templates/> </xsl:template> 
<xsl:template match="dvd/filenumber"> <xsl:text>[</xsl:text> <xsl:text></xsl:text> 
<xsl:apply-templates/> <xsl:text></xsl:text> <xsl:text>]</xsl:text> </xsl:template> 
D134

My main problem seems to be the proper incantations and in the right order.
What is the relation between the <xsl:template>-definitions and the xml-processing, because these data show up in the result?
What is in this respect the function of macros like \defineXMLenvironment, etc? From the example document I cannot infer the relation between these and the <xsl:template>-definitions.
Just some pointers in the right direction may set me on the right track. Thanks in advance.

Hans van der Meer