98 Grand Voyager Keyless Remote

I need to know how to re-program a keyless entry remote that I was given for my 98 Grand Voyager. It's from another 98 Chrysler model but the remote model/item # matches mine so it should be able to work....problem is...I don't know how to re-program it to match my original remote. Any suggestions? I've followed the instructions in my owners manual using the original working remote but I'm not having any luck. Any suggestions would be most helpful!
Thanks...:p