Permanently changing keyboard layout

Hi!
A few days ago I decided to change my keyboard layout. I’m running the i3wm minimal edition, which comes without Manjaro Settings Manager, but I remember that that had a good GUI for changing layouts and installed it. Obviously it works, but there doesn’t seem to be a way to make the change permanent - as soon as I reboot the machine, I’m back with the layout I chose at install time.

Running

sudo setxkbmap -layout us

as the exact same effect.

How do I make the change permanent?

Thanks in advance!