TIP: The Standard and Formatting toolbars may share one row at the top of the window.
Some buttons may be hidden:
To see all the buttons, click the Formatting toolbar's handle (the light gray dotted vertical line)...
...and drag the Formatting toolbar down so it occupies a second row.
Now the toolbars should be stacked one above the other:
To see what an icon does, rest your mouse on it for a full second. A yellow label will appear that tells you what it does: