to follow the animated rain tut and it says to set layers to screen and change opacity whats set to screen mean and how do i change opacity?

On your layer palette at the top left there is a pull down menu that should say "Normal". Click it and it should say:

Normal
Dissolve
--------
Multiply
etc etc etc...
SCREEN
etc etc etc...

Select screen.

Right next to that is a bar labeled "Opacity". Select the "100%" and change it.


It's the Layer Blending Mode and Layer Opacity (Transparancy)