ill take pics if i remember tomorrow, but its pretty simple.
yours may be different, but here's how i get the lower and gearbox out of mine:
remove the barrel
fold the stock
remove the plate covering the rear of the gearbox (difficult with just hands, but easier with a tool)
(this is about as far as you need to go to switch the main spring out)
press the button you see below where the plate was and start pulling down on the pistol grip, separating the receivers (only go a couple centimeters to make enough room to separate the wires from the hinge)
at this point, disconnect the 2 w