You could make an xorg file, but as I said just make this file in this file path /etc/X11/xorg.conf.d/30-touchpad.conf
You can call the file what you want, the number in front is for ordering if you ever add more config files.
Just make that exact file with the touchpad conf I gave before, restart x by rebooting or restarting lightdm (reboot is probably best) and you should be golden