Doris won't lend you a book unless you have a library card.
Look around. There's one lying on the floor. ?
Go to science fiction section.
At the science fiction? Good. It just doesn't work yet. It doesn't have detective's picture in it.
Attach it to the library card.
Glue it there. ?
You find glue from the hobby section table on third floor.
Combine glue with the old library card. Combine the photo on the sticky library card. You have Paul's library card.