I just tried to open the shutter from the backside. But when I did that to remove the blade shutter, I have no way to continue. The pic is as attached. the first three is the front adapt ring, which cause I have no idea to open it from the front. The last is where I can not continue. I have removed the 3 pieces of shutter blade. But I can not continue. Please advise.

adapt ring.jpegoutside.jpeginside.jpegshutter blade from back.jpeg