I dislike to MS tabbed look and would like to change back to the LibreOffice look but I cannot find any information. The only thing I find is how to enable the tabbed look.
Did you follow the steps to the dialogue so you could choose something else?
If the menu is not visible, then click the menubar icon (top left next to Open icon) to toggle visibility
From the menu, click View > User interface and make your choice, I suggest Standard Toolbar. Apply to All
I found a suggestion to enable menubar, then select View and User Interface. All set.