basically you'd sleeve the neg in a material like an uncoated plastic, or something like archival polyester. the sleeve used on the film wouldn't be a tube, but would be a locking type sleeve, like a "fold lock" or a similar product. being able to insert the film lengthwise into a sleeve, then folding it shut, is a way to prevent potential scratches by sliding into a sleeve, and you also get around having to deal with any slip agents or additives in the notebook page being in contact with the film.
you can use the tube stuff, but you lose any benefits over using a standard page.