That looks like a 9x12cm plate holder to me!
Can you read what's written on the lens?
The thing which looks like a polaroid back is a film pack magazine. Film packs have unfortunately been out of production since around 1950.
There are basically three ways to use these cameras: With plates, or with sheet film, or with a rollfilm back.
Plates are still available, but very expensive - adjusted for inflation, they cost almost half of what they did in 1930!
www.retrophotographic.com had some plates last time I looked.
Sheet film can be used with special "film sheaths", which are sometimes found on ebay - especially ebay.de. Film can also be used lightly attached to some firm support, I use orange marmelade for attaching film to glass plates up to 30x40cm.
Roll film backs can also be found once in a while, but like many useful things they tend to come as a part of a package - often including a camera.
But it's worth it - here's a picture I took last winter with a 9x12cm plate camera, using a Slavich glass plate: