Defining the menu in BOA.
If you go to the application created with BOA, the login screen appears. After login the iAPI must respond with a json which contains different elements. One of these element is the menu system.
At that time you have the user who wants to login, so you can adapt the menu according to the needs of this user. The menu for the accountant can be different according to a salesman. This way you can implement user rights on a first level, the menu system.
See the documentation on this page to get more info about the definition of the menu of your application.