Drupal’s menu system takes care of access and permissions for the menu sets you create. Adding new items and sub-items is quite easy. You can find more information about how it works on the Drupal handbook page about the menu system.

However, there are times where you wish to display menus in a fashion which goes beyond just a standard Drupal block.

Here is a link to a video about enhanced navigation using contributed modules on Drupal.org. The video is about 18 minutes long and provided by GotDrupal.com.