if it snapped while she was driving or the car was running theres a good chance you bent a valve.
id get the head checked out,
as for how to change the timing belt...
http://lmgtfy.com/?q=change+timing+belt+and+water+pump+integra
not only is there a plethora amount of information on google, but also on this site.
not trying to come off as a asshole, but its annoying getting the same question everyday when you have so much information that you can access faster than it would take us to tell you.
welcome to clubintegra :thumbs up