There is a selection for automatic updates under Settings > Software Update, but I swear it does nothing on my distro.
If you really want to have auto-updates you can look into systemd unit files. All you need is a very simple one of those, a script that handles the update(s) and to enable it once via systemctl enable --now.
I recommend to disable the notifications and update manually at sensible times tho. You don’t want updates to unexpectedly break stuff and auto-updates are exactly what does that.