xilinx setup

Hello everyone,
I installed xilinx 12.2 yesterday on my desktop. After installation a message popped up mentioning " The environment variables are written to the settings32.(c)sh file for each application and an encompassing settings.32(c)sh at “/home/trans/ISE_DS”. In order to set the variables in your environment, you must source these settings32.(c)sh files from “/home/trans/ISE_DS”. I didn’t understand. What am I supposed to do now.
Also in the settings file its asking to set LD_ASSUME_KERNEL value and what is the path of LD_LIBRARY_PATH?
And how to start xilinx? I’m a Linux newbie, Please guide me
Thank you