How to use these clips in image ready: 

1. Open the clip you want to use in image ready (it should display 5 frames and 5 layers now) 
2. Open the icon you want to use the rain effect on. 
3. Copy the icon and past it in the rain animation. Make sure that all the rain layers are on top of the icon 
4. Set all the rain layers to "screen" 
5. Past the icon on the rain animation again, but this time on top of all the rain layers. Set it to "soft light". 

Now you should have an icon with animated rain. If you are not happy with the result you can try different settings for the top layer. With some pictures "overlay" works better than "soft light" with others it looks better when you reduce the opacity of the top layer a bit. 

6. Make sure to adjust the color setting before you safe the icon, otherwise you end up with a weird greyscale result. 

For a "rain behind a window" effect like the one I got on some of the Harry Potter icons: 

1. - 5. see above 
6. Add an aditional layer of the icon on top of everything. Leave the setting on "normal" 
7. Select the eraser tool and carefully erase the areas from the top layer where you want the rain effect to be visible (like, the glass of a window)