Use the wrench to unscrew the retaining ring, use a needle-nose pliers to pull out the backplate assembly as a unit, turn the capsule over on a CLEAN surface, and the diaphragm and the very thin, transparent spacer will fall out.
The spacer is very easy to lose, and static-cling to your hand, clothes etc.; keep an eye on it and place it somewhere it can't get disturbed.
When re-assembling, the side of the diaphragm with the metal ring goes to the front, then the clear spacer, then the backplate assy, then the retaining ring.
You want to make sure no dust or debris gets between the diaphragm and the spacer, or the spacer and the backplate.