The impossible project 8x10 film is actually packaged very much like the old Polaroid film. There is a negative in a black sleeve, and a separate positive, or receiver sheet. The only difference is that the positive sheet is transparent, not opaque white like the old Polaroid.
Load the negative in the film holder and expose it just as it says in the instructions for the 81-05. Sliding the positive into the film holder afterward is a little tricky because it is not as stiff as the old Polaroid positive sheet. It's frustrating at first, but it can be done and after a few shots you get the hang of it.
Clean your rollers after every shot, the impossible film is pretty sloppy.
Here are some portraits from our Impossible 8x10 workshops, using the 81-05 holder in the 81-12 processor: