Replacing stock speakers? 96 Reg Cab

Ok i want to replace the front door panel speakers and the two rear speakers in my 96 Sierra reg cab. How do i remove the door pannel to do this and how do i get those caps off the rear speakers?? Anywhere i could maybe find step by step instructions? Or if you guys could give me as detailed an explenation as possible that'd be great.

I also need to replace the speakers in my 97 SLE.
I've seen the door instr. in the forum but what
I could use is the replacement speaker dimensions.