Here is how to Make the Aperture work on a Bronica SQ Lens.
See the 5 Steps Below;

1. You will have to move a slider switch on the lens (see red circle below) Some SQ Lenses you have to lift a safety tab or unscrew it to move the slider to the “A” position

2. Now you have to slide the two blue circled tabs (As shown below) to the green dots.

3. Once you slide the tabs too the green dots you have cocked the shutter of the lens. now you will have to release the shutter.

4. To release the shutter you will have to press in the release tab in the mount (Shutter release Tab circled in the green below) press the tab and then you will need to push the two tabs away from the green dots while pressing the tab  it will release the shutter and the shutter should be open in the lens.

5. Now you should be able to use the aperture on the lens with the shutter open, now you are ready to put the Lens onto the adapter. And you are ready to put your adapter with lens onto your camera and start shooting in fully manual mode.