Overview of the Opera browser interface
After the first launch, you pay attention to the "Express Panel", as well as to the sidebar, in my opinion, both are implemented very conveniently. The sidebar contains buttons for quickly launching useful and frequently used functionality, such as viewing history or bookmarks. This panel can be detached from the left edge of the program using the corresponding button at the bottom of the panel, in this case the sidebar will be displayed only on the tab with the "Express Panel".
In order to open the program menu, click on the Opera icon in the upper left corner of the interface.
In the upper right corner of the "Express Panel" there is an "Easy Setup" button for quick browser settings, where you can, for example, change the background or change the theme (a lot of options are available).
In general, the Opera browser is not inferior to the leaders in terms of basic functionality; it is also quite convenient and easy to use.