Navigating beyond the Ribbon

You can choose a file from the list of recently used files by pressing the number to the left of the file name.
The Microsoft Office Button is at the top left of the window (just where the File menu was), and you can get there by using Key Tips, the TAB key, or arrow keys. There are Key Tip badges (and also underscored letters) in the menu to show you which letters to press to use a command, just as there were on menus in previous versions of Office.

Here's a brief list of other keystrokes you need for moving around. Use the TAB key and arrow keys to navigate a dialog box.

Activate a command by pressing ENTER. In some cases, this opens a gallery or menu so you can choose what you want and then activate it by pressing ENTER again. For some commands, like the Font box, pressing ENTER puts the focus in the box so you can start typing, or use the arrow keys to scroll through lists. Once you've got what you want, press ENTER again.

CTRL+TAB cycles through the tabs in a dialog box.
SPACEBAR selects and clears check boxes.
SHIFT+F10 opens the shortcut menu, which opens when you right-click an item.
ESC closes an open dialog box or shortcut menu. If nothing is open, it takes the focus away from the Ribbon and back to the main document.
To close a task pane, first press CTRL+SPACEBAR to open the task pane menu. Then press C to select Close on the menu.
ALT+F4 (pressed simultaneously) closes the active window.
F1 opens the Help window.