If you're asking what it does:
Once installed the client will download a work packet and then begin to work on that packet, which can take some time depending on the speed of your computer to complete. You can view the status by double-clicking on the icon in your Systray or hovering the mouse above it.
Basically, the program will download a packet from Stanford University which it will then process and
fold. The packet size will depend on your processing speed. Once the packet has been folded, the program sends off the results and receives a new packet, all automatically.
Just so you know, the program feeds off idle processing power. I haven't experienced any slow-downs at all.