Hmm use this in your templates: {$var|getnavigation:'page':0:2}. Change the number 2 to any number you want. This is the number of levels of depth. So with 2, you can go two levels deep in your navigation.

To get a cascade menu you should then use css to style it and when you hover on a menu, the children menu should show. There are a lot of css examples on the internet. But you can't copy/paste them because the menu is generated by Fork CMS so you'll need to change a few selectors in the css.