Ok the first time you take the door panels off you might have a bit of a problem. You myst take all the screws out first. Should be 5, 3 on the bottom, one behind the door lever, and then one up near the front pillar. The door lever must also come off. One screw holds it on so it is not too hard. The difficult part will be the window lever. I suggest getting a panel trim removal tool set and to have the proper tool to get the lever off.
Once the screws and levers are off the next thing to do is lift the door panel slightly upwards, about an inch or so. Then the bottom will swing out and then you can pull it off completely. Take your time with that. Now that gives you access to the speakers. Try to not cut the factory wires. Crutchfield and several other places ahs an adaptor that lets you just connect the new speaker to the factory wires. I do suggest going to crutchfield to check the sizes of your speakers and what will fit. I installed new speakers in my truck a bit ago and it was not that difficult after I realized how to get the door panels off. Now the rear speakers might be a pain to get too. You will have to remove the upper rear trim piece first, then the lower trim piece. It can be done with the tray still in the back but it is a pain in the tail. If you can remove the storage tray that would make life easier. The back speakers should be 5 1/4" ones. The front ones should be 6x8. With adaptors you can install 6" full range speakers in the front, and the same in the rear.