Help: Render Target Lookup Tutorial - Confusing

Iam following the wiki tutorial Render_Target_Lookup to implement water physics.

I got a material generating a heightmap, and now want to write that heightmap to a renderTarget (Tutorial step 2).
But i have no idea what the author ment with the following:

So i created an actor. I added two components: SceneCapture Component 2D, Material Billboard.
But what now? i cant “connect” both together, the tutorial misses the most important part here. What am i supposed to do with those two, to render my material on a renderTarget?