Choosing the correct keymap on IPFire 3 initially would be done on the first boot during the setup wizzard.

If there are any reasons to change the keymap at a later point again this easily can be done by the *localectl command which is part of the used init system systemd.

The current settings can be shown as following:

localectl status
   System Locale: LANG=de_DE.UTF-8
      LANGUAGE=de_DE:de
      VC Keymap: de-latin1-nodeadkeys
      X11 Layout: de
      X11 Model: pc105
      X11 Variant: nodeadkeys
      X11 Options: terminate:ctrl_alt_bksp

You safely can ignore all that X11 stuff because we do not own a graphical desktop environment.

To get a list of all supported locales and/or keymaps you can use

localectl list-locales
localectl list-keymaps

And to change to your preferred locale and/or keymap type

localectl set-locale <YOUR PREFERED LOCALE>
localectl set-keymap <YOUR PREFERD KEYMAP>

The changes instantly take effect and are persistent after a reboot.