Very simple. From some of the greatest radio-telescopes of the world millions of data are collected that are then sent to users that use this screensaver to process them and search for regular patterns.
Participating in the project is totally free and very straightforward. Install the screensaver and when your computer isn’t busy it will work on the SETI project. The program will show you detailed information of the process with graphics in real time and numerous data from your evolution in the project.
The tiniest possibility exists that your PC is what detects a signal from extraterrestrial life from the great beyond. But it exists! A scientific environment for your PC that surely will arouse the curiosity of those that see your new screensaver.