make menufile (save as menu(.txt)):
*[[wiki:start]]
*[[wiki:p1]]
*[[wiki:p2]]
*[[wiki:namespace2:start]]
*[[wiki:namespace2:p4]]
*[[wiki:namespace2:p3]]
*[[wiki:namespace2:namespace3:start]]
*[[wiki:namespace2:namespace3:start]]
It is just an unordend list to your pages.
Place in sidebar (point to sidebar(.txt) in your configuration as the sidebar page..):
[[wiki:start]]
[[wiki:namespace2:start]]
[[wiki:namespace2:namespace3:start]]
{{navi>menu}}
When you klick on [[
wiki]] te following is shown :
*[[wiki:p1]]
*[[wiki:p2]]
an so on ....
This should help you up and running.
(Maybe some typo)
Edit : you should have some starting page in your namespace.