How do I suspend or hibernate a desktop PC

[Grandpa]

I plan on leaving my computer on all the time.  But I want to use as little power as possible.  So I went to "Configure My Desktop" > "power Management".  It seems to be mostly about laptops.  But since I use settings there to blank the monitor, maybe it do what I want.  What do I want, you ask.  Well I want to use as little power after a set time of inactivity.  Then when I move the "Mouse" I want it to power back up to where I left it.
So can I do that from configure my desktop > power management?  Do  use suspend or hibernate.  I searched " suspend, hibernate".  Like I said it returned things mostly about laptops.  The more I read the more confused I got.
I am running 2012.08 kde the complete OS fully updated.  I have 4Gb of ram and when I installed the OS I let the installer make all the default settings.  Thanks for any replies.

[Just17]

Suspend to RAM which is 'Sleep' on the shutdown menu, will power down various devices of the PC while retaining the OS in RAM.
If you power off then you lose everything.

Suspend to Disk which is 'Hibernate' on the shutdown menu, saves the current state to the Swap partition, thus allowing full power down, and when rebooted, will boot up the saved state.

Best suggestion I can give is to set the time outs for the various settings to 1 minute while you test to see if they are operational.

The functions and how well they work are dependent on your hardware as well as the kernel in use.

[Grandpa]

Thanks Just18!  I was in the right church just the wrong pew.

[Just17]

Thanks Just18!  I was in the right church just the wrong pew.

[Keith Logan]

Grandpa,

Another small point, you'll need to make sure your swap partition is larger than your total ram so that in worst case it can hold all the info contained in ram. If it was set automatically it may need to be increased manually.

Keith,
the happy chappy