On a toolbar, the focus will always go to the first button on the left, and you can then move within the toolbar by using the TAB or arrow keys. When you reach the end of a toolbar, the focus will go back to the start. Hence, in certain situations, it is much quicker to go backwards through the toolbar by using either the LEFT ARROW key or SHIFT+TAB.
As shown in the example on the left, some toolbar buttons have a submenu off of them. This is indicated by a small triangular down arrow next to the button. To open the submenu, move the focus to that button, and press the DOWN ARROW key. You can then move around the submenu using the TAB or arrow keys.
Once you have opened a submenu, you can move to the next button along the toolbar by using the RIGHT ARROW and LEFT ARROW keys. The TAB key will not work in this case because it would just move the focus to the next command on the submenu.
To select a toolbar button or submenu command, simply move the focus to that button or command and press ENTER.
If you have moved the focus to a toolbar and then decide you don't need to use the toolbar, you can return to your document by pressing ALT or ESC.