I have downloaded the latest stable version for 16-04, according to my Terminal.screenshot Where is the Opera button? I know there should be an Opera button in the top left of the browser so I can set preferences. Not there. Has anyone any suggestions?
The page you are looking at on the screen-shot is an old version of Opera with a totally different user interface.
The Opera version you are using does have a button in most desktop environments, but in Unity, which is what you are using, there are regular menus instead. Hover with the mouse over the title ("Getting started with Opera - Opera"), and the menus will be revealed.