After having set-up multiple keyboard layouts how can I switch between them using a keyboard shortcut?
Default shortcut for switching layouts is Alt+Space.
If you’d like to use a different shortcut, you can set one in System Settings -> Keyboard -> Shortcuts -> Universal Access as “Next Keyboard Layout”.
However, it is not possible to select shortcut Shift+Alt or Shift+Ctrl.
You can do this through the terminal, but I strongly not recommend doing so, because you may have problems with other system shortcuts. If you still dare:
gsettings set org.pantheon.desktop.gala.keybindings switch-input-source "['<Alt>Shift_L', '<Alt>Shift_R', '<Shift>Alt_L', '<Shift>Alt_R']"
gsettings set org.pantheon.desktop.gala.keybindings switch-input-source "['<Ctrl>Shift_L', '<Ctrl>Shift_R', '<Shift>Control_L', '<Shift>Control_R']"
see youtube (in dutch) https://www.youtube.com/watch?v=9c8vHVE_mtA go to system then keyboard then division left corner under you see a +-sign, click it then you will have a new window in witch you can choose a keyboard after having choosed click "add division" in the left column will appear the new keyboard