I am a noob user with post editing images. I don’t know what nodes to use when adding one alpha rendered image on the another rendered image on Blender post processing (compositing). How do i combine these? Or how do I use masks as well here? For example if I have a rendered wall, where is a window but I want to change a scene behind the window. I fell lost if I can’t find a proper tutorial about these things. Thank you in advance.