I just started using AE yesterday, and am still trying to wrap my head around it. I used to do all my compositing directly in FCP, and am trying to learn to do it the "right" way now So I am created a TV in photoshop, and have a really long film strip type thing that I want to run behind the screen part of the TV, horizontally. I no that in FCP I would open up the nested TV psd and put the film strip behind it, and make the screen of the TV not visible. In AE, I am wondering how to do this. I have a feeling I would use a mask or an alpha channel, and am still trying to figure it out in AE. Any tips would be awesome!