How much do you know about 3D modeling? Learn what are points, lines, segments, polygons and what you can do with them. Learn the basics first since most programs are based on those basic principles. And saying "i want to learn C4D", you should be more specific on what you want to learn. You start with basic shapes, since more complicated forms are usually composed of those. Learn what are the limitations and create, best way of learning. We can't do it for you.
https://www.youtube.com/watch?v=tYHBiNsEyxsMaybe even start in blender, its free and offers quite a lot.
https://www.youtube.com/watch?v=LLV7h-WLIx0