Installation

sudo apt-get update && sudo apt-get upgrade

sudo apt-get install ntp

sudo systemctl stop systemd-timesyncd

sudo systemctl disable systemd-timesyncd

sudo systemctl stop ntp

sudo systemctl start ntp

sudo nano /etc/ntp.conf

                    server 0.ie.pool.ntp.org
                    server 1.ie.pool.ntp.org
                    server 2.ie.pool.ntp.org
                    server 3.ie.pool.ntp.org
                    

sudo systemctl restart ntp

To check if time is synchronizing properly.

ntpq -pn

Documentation