SuperCollider needs a couple of directories in the directory from which it is being started, so our first step is to create them so that it can store its stuff there. SuperCollider will not be able to start if it does not find these directories.
So, in a terminal, first change your working directory to your home directory and then create a directory tree to hold the SuperCollider files:
cd mkdir supercollider cd supercollider mkdir synthdefs mkdir sounds
You can select any name for your base directory (~/supercollider/ in this example), and locate it anywhere in the filesystem, as long as you name the enclosed directories synthdefs/ and sounds/. You will need to be in that base directory when you start SuperCollider.
We will be running SuperCollider from inside emacs. The SuperCollider package comes with a special emacs sclang mode that will let you interact easily with SuperCollider. So, start emacs and add this line to the end of your emacs configuration file ~/.emacs.
Save the ~/.emacs file and restart emacs in sclang mode:
Emacs will start with two open buffers, the bottom one (named *SCLang*) will report the output of sclang and the top one (named *SCWorkspace* and labelled "SuperCollider Workspace") will be the first blank canvas in which you can type SuperCollider commands.