All I need to do is place a video with green-screening onto a plane in a scene. Obviously, the green screen will need to be transparent. From what I understand, the video must be keyed and then exported/re-imported because Blender doesn't do keying while rendering. I seem to have successfully accomplished keying in Compositor, but now what? How do I apply it to the plane?

Most info I've found about the subject provides general guidance but doesn't describe the actual *how* to do it.

The scene is animated; the video must play with the rendered animation. The man will appear to be walking up the plank to the ship:

[![Blender green-screening video onto a plane screenshot](https://i.stack.imgur.com/awZeM.jpg)](https://i.stack.imgur.com/awZeM.jpg)