How to set admin menu in new Admin UI

I prefere to use separate file for this (admin_menu.php), but it's only personal prefence because I often edit more files at once or copy from one plugin to other one. 

'divider1' => array('divider'=>true),

'main/prefs' => array('caption'=> 'Settings', 'perm' => 'P', 'url'=>'admin_config.php'),

'main/create' => array('caption'=> 'Add rel.URL/Shortcut', 'perm' => 'P', 'url'=>'admin_config.php?mode=main&action=create'),

'main/list' => array('caption'=> 'Add rel.URL/Shortcut', 'perm' => 'P', 'uri=>'admin_config.php?mode=main&action=list'),

Whar is difference between url and uri parameter?

Warning. With php 5 you can't use concatenate functionility.