SLIME is started with the Emacs command M-x slime. This uses
the inferior-lisp package to start a Lisp process, loads and
starts the Lisp-side server (known as “Swank”), and establishes a
socket connection between Emacs and Lisp. Finally a REPL buffer is
created where you can enter Lisp expressions for evaluation.
At this point SLIME is up and running and you can start exploring.