There is some information in the Cern TWiki.

Register your CERN NICE account for TS access:

• go to https://cern.ch/winservices/tsc/Tools/Register.aspx
• enable Terminal Server Access
• request access to Custom Terminal Service CERNTSLHCB01 (clicking on the “Send Request” link will give you a form at the bottom of the page. Fill this in and send the mail.)
• Wait some time for access to be granted (you probably don't get a mail)
• After 30min or so try to login

on lxplus run

rdesktop -d CERN -k ch-de -g 1024x768 -T "NICE TS" cerntslhcb01.cern.ch

(you probably want to adjust the keyboard layout

You might need to prepare SSH access: http://cvs.web.cern.ch/cvs/howto.php#accessing-ssh

Start a shell using the LbLocal icon on the desktop