请问www.pool.ntp.org时间服务器应该如何安装！

我现在准备了5台服务器准备加入www.pool.ntp.org这个网站的时间同步服务，网站要求安装APACHE，WEB服务器我已经配置好了，但是后面的配置我就不知道了。
这是官方的方法。但是我不是很懂。麻烦会的朋友告诉一下。谢谢！

Setup about 5 servers
To work properly ntpd needs to talk to at least 3 servers ("A man with a watch knows what time it is. A man with two watches is never sure").

For servers in the pool we recommend configuring no less than 4 and no more than 7 servers.

Don't use *.pool.ntp.org servers
Ironically to make sure the pool service is the best it can be you shouldn't use the *.pool.ntp.org aliases in your configuration when you are going to add your server to the pool.

For the robustness of the pool it's healthier if all pool operators "hand pick" good local (network wise) time servers. The NTP.org wiki has a list of public servers.

Use the standard ntpd
We are all for software diversity, but a significant percentage of the "it's not working" questions that come in are for software other than ntpd.

You can use the pool with any program speaking NTP, but if you are going to join the pool we recommend you use ntpd.

Don't use the LOCAL clock driver
Servers in the NTP Pool should not have the LOCAL clock driver configured.

是不是要安装个ntp来同步时间啊？
#cd /usr/ports/net/ntp
#make clean

ntpupdate xxx