PSD Files

Hiii. I was wonderingg if there are any tutorials on usingg a .psd filee? I'm stupid and can't seem to figure it outt.
I havee PS CS2.
Thank yooou. :)

EDIT:
to clarify what I mean: When someone saves a .psd file and you download it..how do yoou use it to make your own icons with that filee?