No better way to get started in C4D than by following along with a 3D type tutorial, like this one which shows how to create glass type.

Cinema 4D Artist Niko Schatz has a look at how to create glass type in Cinema 4D, using the almost forgotten physical renderer.

Niko shows how to create the type, and build the glass shaders for it, set up the scene with lights, and finally render. Niko shares some render settings for the physical render that will help speed things along.

Niko also shares the scene files which can be found here.