Ninja Modulizer is a so called module extension.
If the installation went correct then you can find Ninja Modulizer in the Module Manager after installation.
Very strange you can't find it.
What comes up in mind is could you check if Ninja Modulizer is there when you use the dropdownbox within the Module Manager at the bottom of the page which says 'display' and set this to 'all'.
If this is the case then you can find a usage description under 'Dashboard' on the right-side where the module parameters are.
I hope this helps. Let us know how it goes.