You need to store your Audioscrobbler username and password in the
config file:
 echo -e "user: foo\npassword: bar" > \
 ~/.config/xmms2/clients/xmms2-scrobbler/config

Optionally, if you're behind a proxy, you'll need to tell
XMMS2-Scrobbler about that proxy:
  echo -e "proxy: my.proxy\nproxy_port: 8080" >> \
  ~/.config/xmms2/clients/xmms2-scrobbler/config

If you want to launch and stop xmms2-scrobbler with xmms2d you can
execute:
  ln -s /usr/local/bin/xmms2-scrobbler ~/.config/xmms2/startup.d

Log will be saved in ~/.config/xmms2/clients/xmms2-scrobbler/logfile.log