Basically I have a particle layer doing its light streak effect, I need that to be like at layer mask in photoshop. So it will show a very high-detailed text layer behind its streaks. How do I set this up? I tried track matting and it seemed to be the right direction, but I don't think I did it right. Any thoughts or ideas?
From what I can understand, a track matte is indeed what you want.
A track matte will use the pixels on the layer as transparency for the layer below (using alpha or luminance).
So if you have the particle streaks and use that as a track matte for something else, the particles will not be shown at ALL but will be a mask through which the other layer shows.
Well okay, but here is the problem. I don't want to see the entire layer below until the hand has "particulared" itself over the that part. I photoshopped a frame to show you what it should look like. The bright pink text would be the bottom layer that is "being" revealed while the lightstreak masks its way over it.