Missing CMS Menu Manager needed for Gantry5

Hello community!

Can anyone tell me, where i can found the CMS Menu Manager in Grav. As written in th Gantry Documentation, i need to create a menu in grav, then i can style it in gantry5, but i cant find any possibility to create it in grav… and the menu editor is empty, as you can see here:

Thank you very much!