Use Library Search to find the collection (e.g. Main Collection) and the shelfmark of the book you want to find.
The shelfmark is printed on the spine of the book and is made up of a number and three letters. You need the whole number and the letters to find the book.
Example: Transforming Behaviour in the Classroom by Geoffrey James has the shelfmark 371.1024 JAM.
The number indicates the subject: 371.1024 = classroom management.
The letters are the first three letters of the author's surname: Geoffrey JAMES.