J5 + Shaper_helixultimate - Submenu in Burgermenu not available

[ds2k5]

Hi,
using Joomla 5.2.2 with Shaper_helixultimate version 2.1.1
how to add Submenu in Burgermenu ?

Mainmenu:
Company -> about us
Company -> contact
Calendar -> add appointment

In Burgermenu I can see only: Company or Calendar not more no Submenus
This is needed for Mobile Devices (Tablet / Smartphone)

How to enable Submenus in Burgermenu ?