Prerequisites for this are knowledge about Acl and Controllers.

This tutorial shows you the required steps to create a menu item that shows a custom ExtJS class (based on Ext.Panel)

Create Ext.Panel based class

Example.Foo = Ext.extend(Ext.Panel,
    initComponent : function()
        console.log(this.testParameter); //passed by indexAction

        this.html = 'foobar';

Ext.reg('example.foo', Example.Foo);

Create Controller

class Example_FooController extends Kwf_Controller_Action
    public function indexAction()
         //pass any parameters that will end up in Panel config
        $this->view->testParameter = 123;

        $this->view->xtype = 'example.foo'; //refer to xtype registered with Ext.reg()

also see start controller

Create Menu Entry in Acl that links to new controller

$this->addResource(new Kwf_Acl_Resource_MenuUrl('example_foo',
                array('text'=>trl('Foo'), 'icon'=>'user.png'),