Hi, I'm still very new to my large format camera, and whilst I was taking out the negative holder, the focusing screen mount came off from the braflok spring back (as far as i can tell this is what it is called). I do not know how to put it back on or even if i have damaged something. Could somebody take a look and advise me as to whether it's damaged or how it goes on, the manual does not say. I'm not sure how it's spring loaded, or if it's a spring at all - i was pulling it outwards to access the negative holder when it came off. attached are photos.