You should be using Adobe’s Dynamic Link feature for this. Which version of the softwares do you have?
Essentially, if you want to render out with transparency, you’ll have to choose a CODEC that supports an Alpha Channel. QUickTime’s animation CODEC does that.
For now, come back if you need more info and we’ll see if we can sort things out for you. In the future, please use the COW’s AE Basics Forum since you are new to AE.
Cheers
RoRK
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