Add widget to header area

Hello,

I am using the navigator template with elementor and have my header as a vertical menu to the left.
I am looking to add a menu list below the main one (styled differently) in my header and tried playing around by adding widgets to the header area.
I tried the Nav/Menu Widget and the Custom HTML but I can't save due to an error.
Attached is a screenshot of the error and an image of what I am trying to achieve:
- issue: https://snag.gy/cYq7dn.jpg
- goal: https://snag.gy/2o7O6Z.jpg