Whether your logo or idea is already in a jpeg or vector format, or drawn on a napkin, it will be traced into a spline shape in Cinema 4d. Then, it is extruded into a virtual three dimensional shape - a mathematical representation of a real object.
Think of texture of a model as a kind of skin that covers the outside. It can be made to look metallic, plastic, transparent like glass, to name just a few possibilities. Without textures the model will simply be gray and flat.
No matter how well your model is made and textured, without lighting, no one will ever see it. Finding just the right mood of lighting is an important part of making a beautiful logo stand out.
Rendering is the computational process of calculating what your final scene will look like, taking into account texturing, lighting, and the model itself. It is the conversion of the mathematical model into an image you can see.