For the TOC GoTo menu item, you'll need to have a corresponding guide item in the .opf file:
Code:
<guide>
...
<reference href="Text/TOC.xhtml" title="Table Of Contents" type="toc" />
</guide>
For direct chapter selection, you'll need a valid .ncx file with links to each chapter. You can generate both automatically with
Sigil, if your chapter titles have been formatted as headings (h1..h6), which are used by Sigil as chapter markers.