there are helpfiles included. (hit cmd.-? in supercollider (osX); for linux cf. SuperCollider Emacs) also there are some tutorials around, like the Cottle examples.
SuperCollider helpfiles are sometimes incomplete. if you have an issue that you'd like to be documented, just either mail it to the list or just add a comment here. We will pass by here sometimes to check for stuff.
For various tutorials, see also: Theory