Adding effect to a transparent layer

[Jdylan423]

Hi. I'm fairly new to After Effects so this question may be basic. 
I have a video and I have a simple silhouette image that I want to overlay on the video. 
I want to add a little movement texture to the silhouette without effecting the video underneath. The image is just black on a transparent background. 
does anyone know the best way to do this?

thanks 

[Joost van der Hoeven]

Hi, welcome to the marvelous world of After Effects!

Maybe this tutorial is a good start?
https://helpx.adobe.com/after-effects/how-to/transparency-luma-mattes.html?playlist=/services/playli...

[Rick Gerard]

Some effects take over an entire layer and ignore transparency, some honor layer transparency. Without knowing exactly what you want to accomplish and which effects you want to apply the only advice I can give you is to try adding the effect to the layer. If that does not work, add a new layer below your layer with transparency, add the effects, then set the transparent layer as an Alpha track matte for the layer with the effect.

If you want to share a screenshot please embed it using the toolbar. Tell us what you are trying to do in detail and maybe we can help.