Then use letters instead of categories, such as military A and computer B, which need to be recorded in tables.

The third step is to number different kinds of books, and it is suggested to go to a treasure to buy books and print them.

Then put a code on each book and put it in order.

If you don't want to ask how to code books, I suggest you go after the American TV series You. The man is the owner of a bookstore. There are many descriptions about the storage of books. And the plot is very interesting.