Quantity - defines how much a shelf is filled with books in percents where 100% means that the shelf is full and 0% means that the shelf is empty


Random - add randomness to quantity between shelves, where 0% means no randomness and 100% means ultimate randomness, where Quantity value has no influence. Bookmanager randomly choose books quantity for each shelf between Quantity-1/2*Random and Quantity+1/2*Random. It allows to get different books number on different shelves. If you wish to get the same result on each shelf you need to specify Random option to 0%.