The roll of 120 comes on it's own spool including a backing paper. In order to load the camera or film back, you need to have a second spool which serves to receive the film from the "new" roll of 120. When the roll of film is finished, you continue to wind the film onto the second spool until the end of the backing paper is wound off of the original spool. Use the adhesive tape to seal the end of the backing paper so that it won't unwind and expose the film to light. Finally, move the empty spool to the "take-up" side of the camera or back and you are ready to load another film.