Pathagoras provides two distinct ways to add ('shelve') a book to the active library.
•If a bookshelf is empty when you are viewing the Libraries & Books screen, you can Quick Set the book. Quick Set automates the process of placing a book onto an empty shelf.
•If you wish to replace an existing book with another, or re-point an existing book to a new location (perhaps you moved the files to a server or to a cloud location), hold down the Ctrl- button while clicking on the book you wish to replace or re-point. This page discusses re-pointing in more detail.
•If you wish to rearrange the books in a specific library, do so via the Settings screen.
Click the button in the menu bar to read more about shelving books.