This has been a recurring topic throughout the years and no - there is not a single "manual" or "compilation" of TG nodes and functions.
The TG Wiki should be a good resource, but it also has many, many holes. Still, it is very helpful, even in its incomplete state.
Functions, only recently have started being explained with Hetzen's (Jon's) contribution. If you are interested, you should jump in the relevant forum section found at the bottom of the general page.