to get some audio fast, follow the instructions below. you must have installed scsynth and sclang and jack must be running for the example to work!
change to the build/ directory in the distribution:
$ cd ~/dev/SuperCollider/SuperCollider3/build
$ sclang ../linux/examples/onetwoonetwo.sc -
when you've had enough, press Ctrl-D. (Or maybe Ctrl-C)
for a basic overview of running sclang and scsynth see Running sclang and Running scsynth.
convenient interfaces to the language application are covered in scfront and SuperCollider Emacs.
the build/ directory in the distribution contains a Help/ directory with online help for classes and a tutorial.