it depends on if you have a 1 piece or a 2 piece driveshaft,in either case raise the back of the truck and put it on jack stands and take the retaining clamps off of your universal joint at the differential,and slide the dive shaft out of the transmission and if its a 2 pieces do the same except you have to remove the center support bearing.when installing the 2 piece with the center support bearing tighten the center support bearing bolts finger tight and start the truck,put it in drive and let it idle in gear for a minute so it can line its self back out and then tighten the support bearing bolts and be careful.

the reason they are refering to front and rear is because some trucks are 4×4 and have two drive shafts. the one you are refering to would be considered the rear one on a 4×4. the front one would connect the transfer case(it attaches to the rear of the transmission)to the front differential. so if you have a 2 wheel drive it would just be called the drive shaft. as far as removal there are four small bolts that attach it to the differential. these are usally 7/16 or 3/8 (wrench size). they actually are retaining bolts that secure a metal clamp around the universal joint to the pinion on the differential. just remove those and stick a prybar it there are pry it loose. hold it because it will fall and hit you if you are not careful. the front portion of the shaft is what is call a slip yolk. it just sildes into the back of the ******. just pull it out. use a drain pan because you should loose some fluid. as far a buying one. you are not going to find this at the parts store. go to the junk yard. should run you between 25 and 50 bucks. hope this helps