[Jellby]

You can add spaces and linebreaks between tags, to make it easier to see. This is where the links are:

<navMap>
  <navPoint id="navpoint" playOrder="1">
    <navLabel><text>iceworldRebaToy</text></navLabel>
    <content src="iceworldRebaToy.xhtml"/>
  </navPoint>
</navMap>

It's a <navMap> element that contains a single <navPoint> element. This <navPoint> has a <navLabel> (this is what would be displayed by the reader in the TOC), and a <content> (this is where the link points to.

To solve your problem, you probably want to add more <navPoints> inside the same <navMap>. Follow the same scheme and give to each one a different "id" (it's enough with things like "navpoint1", "navpoint2", etc.), a consecutive playOrder, and make them point to the right place. And use descriptive texts. You can also change the existing <navpoint>. Something like this:

<navMap>
  <navPoint id="navpoint1" playOrder="1">
    <navLabel><text>Title Page</text></navLabel>
    <content src="iceworldRebaToy.xhtml"/>
  </navPoint>
  <navPoint id="navpoint2" playOrder="2">
    <navLabel><text>Chapter 1</text></navLabel>
    <content src="iceworldRebaToy.xhtml#ch1"/>
  </navPoint>
  <navPoint id="navpoint3" playOrder="3">
    <navLabel><text>Chapter 2</text></navLabel>
    <content src="iceworldRebaToy.xhtml#ch2"/>
  </navPoint>
</navMap>

(assuming you have anchors named "ch1" and "ch2" in the xhtml file.)