Click on "Search" above, and when the screen comes up type in 'countdown clock tutorial' and click on "Search". Then click on the first reply (no. 1) and you'll see the format for setting your clock, compliments of MBuckellew.
Moai, thanks for the site. I checked it out and it appears that the countdown clock is part of the code used to write the site, instead of showing up as an image that we can copy and paste into our posts here. So I don't think it will work.
Hopefully I'm wrong about that site shutting down its countdown clocks.
Now posting as MichelleP.