In practice this is the general order of the picture taking process with a plate camera.

The camera is set up in front of the view on a tripod, many types had a spirit level so that the camera could placed perfectly level. Normally a hood would be thrown over the camera to stop light falling on the focusing screen, making it difficult to see - this has been omitted in these illustrations for clarity. The shutter is set to 'T' (timed, it stays open until released), and then opened - allowing an image to be projected onto the ground glass screen, initially the aperture should be set to wide open. This allows the photographer to focus on the exact point required and compose the image relatively easily, then the lens can be 'stopped down'.

Here, the image has been composed and the Sanderson Camera has been focussed on Teddy, note the projection is inverted.

It's worth pointing out that the back of this Sanderson can be removed and rotated 90deg to allow landscape or portrait format images to be taken, but the lensboard always remains vertical and tripod mounts are only fitted on one side. This allowed the Sanderson lens movements always to be correctly orientated.

Once the photographer is happy with the composition, the shutter is closed and then cocked. Once it is confirmed that the image has disappeared , the focussing screen is withdrawn , leaving the rails free for the plate carrier, as shown in this picture. A final check that the aperture, shutter speeds are correctly set and that the shutter is cocked (if applicable).

Then remove the plate carrier from the safety of its bag, note the number, then slide it into position. Make sure it goes all the way to the bottom and seals correctly. Some cameras have a positive detent location (as does this Sanderson), others have a small catch that is swung out to lock the plate carrier in place. Care needs to be taken during all this not to disturb the camera. The need to ensure a light tight fit means that the mechanism needs to be fairly tight and therefore a certain amount of stiffness has to be tolerated with the attendant risk of moving the camera accidentally in the process.

Here a plate carrier is shown during insertion.

Now the darkslide can be withdrawn, taking care not to open up a gap by rocking it, also make sure that the plate carrier doesn't come out with it as light will get in the bottom and ruin the plate instantly. This is what the little catches or detents on the camera are designed to prevent - but they are only as good as the person using them. The plate is now unprotected and the shutter can be released. The darkslide is now slid back into place. In this example the darkslide is black one side and silver the other, thus the simple expedient of putting the darkslide back in the other way round allows the photographer to keep a check on which carriers have been exposed or not. The Plate carrier should be removed from the camera promptly and placed into the safety of a bag, until the other side is needed or removing for processing.

Modern Cut or sheet film can be used in these cameras with a little ingenuity. Get some 3ply modeling wood from a aero model shop, chop to size, paint matt black then insert into the carriers to take the place of the stiff glass. The sheet film simply sits on top, held in place as normal and the ply prevents the pressure springs from distorting the film.