Contrib packages aren't loaded by default. You have to modify your
setup a bit so that Emacs knows where to find them and which of them
to load. Generally, you should call slime-setup with the list
of package-names that you want to use. For example, a setup to load
the slime-scratch and slime-editing-commands packages
looks like:
(setq inferior-lisp-program "/opt/sbcl/bin/sbcl") ; your Lisp system
(add-to-list 'load-path "~/hacking/lisp/slime/") ; your SLIME directory
(require 'slime-autoloads)
(slime-setup '(slime-scratch slime-editing-commands))
After starting SLIME, the commands of both packages should be available.
The REPL and slime-fancy modules deserve special mention. Many
users consider the REPL (see REPL) essential
while slime-fancy (see slime-fancy) loads the REPL and
almost all of the popular contribs. So, if you aren't sure what to
choose start with:
(slime-setup '(slime-repl)) ; repl only
If you like what you see try this:
(slime-setup '(slime-fancy)) ; almost everything