Andrés Cabrera wrote an article for The Csound Journal called An Overview of Csound Variable Types. This is a great guide for demystifying that various signal types in Csound. There are siz types in all: audio (a), control (k), initialization (i), string (S), phase vocoder streaming (F) and spectral (w). Section II is especially useful as it provides various approaches for converting from one type to another, which you will find yourself doing from time to time.
