How do I hide the top bar?

When I switch to “Tabbed”, ie using the ribbon, I still see the top bar (not sure if it’s called menu bar or navigation bar or else). It is rather confusing since there is the same functionality available twice. When I look at youtube videos of other users, they do not seem to have this configuration. I cannot figure out how to remove the top bar. Can someone help, please?

image description

Test with the top-left icon ‘Menubar’

This works. Thanks a lot!