When implementing your own Acl you usually create a class named app/Acl.php containing a Acl class. Then set this class as aclClass setting in config.ini.

Inherit existing Kwf Acl

Depending on your requirements you can inherit the required Acl class:

Create custom resources

In the constructor of your Acl class add a new resource like this:

$this->addResource(new Kwf_Acl_Resource_MenuUrl('controllermodule_controllername',
                array('text'=>trl('Text'), 'icon'=>'user.png'),
    $this->addResource(new Zend_Acl_Resource('controllermodule_othercontroller'), 'controllermodule_controllername');

othercontroller is added with a given parent, with means users that can access the parent can also access othercontroller.

And then allow this new resource for a role:

$this->allow('admin', 'controllermodule_controllername');

Create dropdown menu items

for categorizing the menu you can easily create a dropdown using the Acl:

$this->addResource(new Kwf_Acl_Resource_MenuDropdown('foo_categoryname',
                array('text'=>trl('Category'), 'icon'=>'user.png')));
    $this->addResource(new Kwf_Acl_Resource_MenuUrl('foo_bar',
                array('text'=>trl('Text'), 'icon'=>'user.png'),
                '/foo/bar'), 'foo_categoryname');