Assuming that you already have a new handle (ie. ordered one or got one from a donor vehicle) you have to lower the tailgate and raise the window (put something under the glass to support it while it is extended or there is a good chance it could crack). You will have to unbolt the regulator mechanism and slide it toward the front of the truck about 1-2". Then if you look down through the gears and you will see 2 small nuts that hold the crank assembly in the tailgate. Remove those and the crank assembly will essentially fall right out. Put the new one in, replace the nuts, bolt the regulator back in place and you should be good to go.