Create a page called "Menu", and add 4 links to other pages (one of them, called "Instructions"). Then add a link in your homepage to the same page "Instructions". Then, in the homepage, add this syntax:
{WIKIGRAPH(level=>1)}Menu{WIKIGRAPH}
You will end up seing something like this:
You need GraphViz
See in action here: http://workflow.tiki.org/graphviz
WikiGraph Plugin | PluginWikiGraph
