Timezone

$ sudo timedatectl list-timezones
...
Europe/Copenhagen
...

$ sudo timedatectl set-timezone Europe/Copenhagen

NTP

$ sudo systemctl start  systemd-timesyncd.service
$ sudo systemctl enable systemd-timesyncd.service
$ sudo timedatectl set-ntp true

Locale & 24 hour clock

$ sudo localectl set-locale en_US.UTF-8
$ sudo localectl set-locale LANGUAGE=en_US:en
$ sudo localectl set-locale LC_TIME=C.UTF-8

Linux console keyboard layout. Note: the console-data package is a prerequisite:

(current session)
$ loadkeys us
(persistent)
$ sudo localectl set-keymap us