Why is the submenu not being created?

Question

1C-Bitrix

I am new to 1C-Bitrix. I'm trying to create a submenu for the top menu item "Products" - "index.php#devices". Actually, I'm trying to create a dynamic submenu, but I'm stuck on the previous step. I did:

1. Created a subtop menu type
   
2. In the settings of the top menu, set the nesting level - 2, the submenu type - subtop, and "Do not cache"
   
3. Created a menu of type subtop in the top directory of the site, added a test item to it
   

If you add items to .top.menu_ext.php c , then menu items are added, but added incorrectly: to an empty menu item. So the problem is not in the menu template. What am I doing wrong? $aMenuLinksExt[$i][3]['DEPTH_LEVEL'] = 2;