Hello and welcome to JustAnswer!
Do you have one key fob that does work?
If you had one fob that was programmed and worked then there is a way to program more yourself. If you don't have one that is programmed then a scan tool is needed. It's like this for security - if it could be done without already having one that is programmed then anyone could program a fob to your truck to get in it.
Without having one fob that does work the only way to program a new one is with a DRBIII scan tool. This will need to be done at your dealer and will only take a couple minutes. At my dealer the programming of key fobs runs $21.