The door panel has to be removed first. If the factory speakers are smaller than 6. 5 inches then you will have to do some machining to get the speaker to fit. Also take into account the depth and power requirements of the speaker before doing this.
You will first need to remove the cover on the speakers to access them. Once you have done that you should be able to remove with your basic screwdriver. Then you can put them back in or replace after you have done this.