I'm not sure what the question is here.. If it is adding the left sidebar use the following HTML code:

Depending on if you want this sidebar to be present in all pages or only on one page:

All Pages

In release 0.9 of XWiki you you just need to create a page XWiki.Menu in your Wiki. It will automatically added to all the pages on your Wiki.

In only one page

You can use the following HTML in your page:

Be carefull not to add white lines between the div blocks since they are transformed into paragraphs by the wiki syntax and Internet Explorer doesn't like it.