Once input-remapper has been installed, it needs to be configured and its 
service unit enabled and started:

sudo systemctl enable --now input-remapper
sudo systemctl start input-remapper


For detailed configuration instructions, please see:
https://github.com/sezanzeb/input-remapper/blob/main/readme/usage.md
and
https://github.com/sezanzeb/input-remapper/blob/main/readme/examples.md


When making configuration changes using the graphical user interface, these can
be enabled in place (by clicking on "Apply").

On systems without a graphical environment, the configuration files will have
to be created manually and placed in /home/<user>/.config/input-remapper-2/
When the service unit is restarted, it should pick up these settings.