To add to or replace the preselected keyboard layout in Ubuntu with the Unity
desktop, follow these steps:

# Open __Text Entry Settings…__ by clicking in the input language menu and
  selecting it:\\
  [images/UUnity_1_open_text_entry_settings-en.png]
# Click the plus sign in the lower left corner of the window to add a new
  keyboard layout:\\
  [images/UUnity_2_text_entry_settings-en.png]
# Select your keyboard (type the first letters of its name in the search field
  to narrow the list), and then click __Add__:\\
  [images/UUnity_3_add_sme-en.png]
# Now you can easily switch keyboard layout and language using the keyboard
  menu (or using the keyboard shortcuts):\\
  [images/UUnity_4_input_menu_with_sme-en.png]