The green glass is a plate, ruined by now

You need film inserts to convert the plate holders although a piece of black card will work.

There were many manufacturers of 9x12 cameras often very similar and quite a few used Rodenstock lenses, & |Rodenstock made cameras as well - I have one, my other an Orion Werks also has a Rodenstock lens, both take similar plate holders to yours.

The I is instant whatever shutter speed is set, the B is bulb, shutters open while the shutter release is depreseed (or cable realease) T is time, forts press opens the shutter, the second closes - usually used for focussing, or like B long exposures. (ZDM is the same but German symbols). DF is because the shutters made by Friedrich Deckel who also part owned Linhof.

Ian