Using vCenter to gather historical performance data

Hi,

We just installed vCenter Server 5.1 and I would very much like to monitor my host's memory, network and CPU usage.

I can see the real-time usage of all these components but most our VMs are heavily used between 10 PM and 8 AM (times when I am not in the office and our automated build system is building using all our VMs). I am trying to figure out how to use vCenter to pull historical (not real-time) performance data.

Can someone:

1. List steps on how to do it

or

2. Point me to documentation that outlines how to do it?

Thank you,

Abhi