I am trying to configure a pc in kiosk mode, one of the things I need is that a nonprivileged user does aotomatic login (autologin), I could configure it following the instructions from here https://forum.kde.org/viewtopic.php?f=66&t=156731, but I would like to setup it in the configuration files. Could anyone give me some directions?

If you are using SDDM, you should add

[Autologin]
User=<login>
Session=<session type>

to your sddm.conf which in most of the distros is located in /etc. Available session types are located in /usr/share/xsessions, usually it is plasma.desktop

Thanks a lot, it went great, i saw that when chaging the setting from the kcm generated the file you mentioned (it wasn't present before). So I am now deploying this file and autologin just works.