Mobile menu not showing

On http://185.224.89.32/~diannevos (Home) the mobile menu is not showing; when reloading I see the mobile menu briefly but it disappears immediately.
The menu should be next to the logo, like this style: https://header-demo.diviultimate.com/style-3/

I also imported the standard style 3 on the about us page: http://185.224.89.32/~diannevos/over-wdpp/
But the mobile menu (hamburger menu) style 3 is also not showing.

I hope you can help me further?

Kind regards
Dianne Vos
Netherlands

 

tx.
gonna try it this way.

Another question: can you tell me when was this new intallation-guide posted or released?