Does jail breaking cause harm to the iPad, I mean like during the process. Because I'm really scared if something goes wrong
No. The jailbreak is only software. There is absolutely no way an iPad can be damaged by the jailbreak despite the scare stories you might have heard.
iPad's are impossible to brick and if you decide that you do not like the jailbreak for whatever reason you can simply restore your iPad using iTunes and it will be wiped clean and back to factory settings leaving no trace that is was ever jailbroken.
Please have a read of our stickies in the hacking section for more info, starting here - http://www.ipadforums.net/ipad-hacking/2838-jailbreak-explained-new-updated-2011-a.html