A lever on the camera body charges the main mirror spring.

The shutter release pushes the mirror release lever.

The mirror flips up into the taking position and the stop down plate is pushed forward.

The arm extending from the top of the mechanism is the opening curtain striker. It releases the opening curtain latch located on the camera body and begins the exposure of the shutter.

The mirror return spring (also on the camera body) pulls the mirror back down to the viewing position.