Making paper bag books is really quite easy. Using 3 lunch bags, stagger them so that the open flap falls to the right, then to the left, then to the right again. Lay them one on top of the other.
There are several ways you can bind your paper bag albums. You can punch 3 or more holes down the left side and later use ribbons to tie them together.
Or you can sew down the center, creating a sewn spine.
Another option is to bind them with a comb binding if you have that capability. Or use metal rings, which you can purchase at scrapbook stores or even hardware stores.
To create additional inside pockets you can use brads, eyelets, glue or even sew down flat bottom portion of the lunch bags. Here is an example from a "found objects" paper bag scrapbook I am working on. See the pocket?