If you're talking about the 2nd gen., fold down tailgate. There are two screws nearest the tail lights, unscrew them and the tail light assembly will pop out.
It should be self explanatory on how to get the old ones out and put new ones in. If you don't know how, have someone in an auto parts store to help you. Afterwards, please invest in an owner's manual. Either the dealership can order you one, or check to see if anyone is selling one on eBay.