To "blend model in video" you need to turn on the Alpha channel generation in Cinema 4D. Then, for every renderend frame, an additional b/w "alpha" frame will be generated and it can be later used as a mask in a compositing program.
Please read the "Cinema 4D - Rendering Menu - Render Settings - Save - Alpha Channel" section in the C4D Manual (Help) system, all you need to know about the procedure is described there.
Lighting tutorials for Cinema 4D? NP, pal. Check out these, for a start...