The Bush Pressman that is due to arrive Wednesday will include a number of 4X5 film holders and a Graphic Film Back Adapter. I am assuming this adapter is to adapt the camera back to 4X5 sheet film loads of a number of films. Is this a correct assumption? There will be no instructions for the camera or the adapter so I will be at a complete loss as to how to use it.... I won't know if parts are missing or what parts should be there. Nor do I have any idea how to load it. Is there a web site or source to learning the loading and use of this adapter? Thanks for any advice.