|Nothing fancy here... set your time and let it do the rest.|
As said, it's a very small utility and comes with a simple GUI which lets you set a count-down time frame and then automatically displays the "remaining" time before the automated shutdown (shown in the sidebar of Unity desktop). However, at this time, EasyShutdown can only be used with Natty Narwhal only!. So if you have an earlier version of Ubuntu... then it cannot be used in those environments, although it could change in the future.
Anyhow, the installation is pretty straightforward. Just download the package from here and double click on it. That's it.