Beneath that is the Top Toolbar with Speed Buttons for frequently used tasks. To see what any Speed Button does, move the mouse cursor arrow over it. A hint explaining its function appears immediately underneath the button. Another explanation, often giving the Quick Key command, may also appear on the status bar at the bottom of the screen.
NOTE: You can customize the Top Toolbar by using the View > Toolbar Icons > Customize Toolbars... menu, or by right-clicking (or CTRL-clicking) on the Top Toolbar to bring up it's Customize Toolbar options.
