Separate the upper and the lower receivers and put the upper out of the way.
Depress the buffer retainer and remove the buffer, and buffer spring from the receiver extention (buffer tube)
As stated above, Top screw will allow you to remove the stock from the receiver extention (buffer tube). Now, there may be some locktite on the screw, so becareful not to strip the screw if you use a drill or power screwdriver. Try and use a large slotted screwdriver.
<READ FIRST BEFORE PROCEEDING>
Now, as you slide the stock off the receiver extention (buffer tube) there will be a small spring/detent that will pop out if you slide the stock off too quickly. This is the detent and spring holding in your rear takedown pin. Once the stock is removed, keep tabs on the spring/detent or it will fall out and you may lose it.
Now you will need a 5/8ths inch wrench on the flats at the end of the receiver extention (buffer tube). If there are no flats, then the Buttcap spacer is still on the end. Pull it off and you should see flats for the wrench. If you see flats and are wondering what the heck I'm talking about, look in the stock and there should be a small cylidrical object. That's the buttcap spacer. If you are using an A1 stock, this will not be here.
Righty/tighty, left/loosey
<READ FIRST BEFORE PROCEEDING>
CUP YOUR HAND OVER THE RECEIVER AS YOU UNSCREW THE RECEIVER EXTENTION (BUFFER TUBE).
The buffer retainer will pop out and if you aren't careful it and the spring will fly across the room and you may never find them again.
That's about it. Large slotted screwdriver and 5/8th inch wrench.