1. Replace
<xsl:for-each select="myPage/navLinks">
<a href="test.html"><xsl:value-of select="title"/></a>
</xsl:for-each>
by
<xsl:for-each select="myPage/navLinks/link">
<a href="{@title}"><xsl:value-of select="."/></a>
</xsl:for-each>
(2) //item selects all the items in the document, and xsl:value-of displays the first thing selected. You want the child item of the current data element, which is just "data".
Both your mistakes suggest that you haven't grasped the concept of relative path expressions which select by navigating from the context node. It's worth doing some reading around this topic.
Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference