Get your keymap, e.g:
wget https://xnybre.dk/keymap/xsk
Then copy it to the appropriate dir:
sudo cp xsk /usr/share/X11/xkb/symbols/
Set the keymap as currently active:
setxkbmap xsk
Make it your default keymap on X startup by adding a file such as /etc/X11/xorg.conf.d/00-keyboard.conf containing:
Section "InputClass"
Identifier "system-keyboard"
MatchIsKeyboard "on"
Option "XkbLayout" "xsk"
EndSection
This will apply the xsk keymap to all X input devices identified as keyboards.