I know there is a GUI for RHEL, but I still prefer to do these things via a command line.

RHEL Setup NTPd

To simply set the time to the time server (correct time one-off), use the following command:
/usr/sbin/ntpdate IP_or_ADDR_of_NTP_Server

In my case it was this command and this result:

-bash-3.2# /usr/sbin/ntpdate 10.4.0.253
18 Jan 08:16:02 ntpdate[13347]: step time server 10.4.0.253 offset 756.199630 sec

As you can see, this server was off by over 12 minutes!

If you want to edit the NTP Servers List:
nano (or vi) /etc/ntpd.conf
Add the specific time server you require
/sbin/service ntpd restart