This package is currently usable. The _access modules provided with this setup are technically demonstration modules; they are there to provide a template for developers to create their own _access modules that can work well together. That said, they are both functional modules and they should work. Hopefully, there will be more. Installing this package is easy: Drop the entire directory in your Drupal modules directory and turn it on. You may need to go to admin/settings/na_arbitrator and 'reset' so that existing content gets the proper access controls.