It is a long process. There are essay questions called "T&E"s or "Training and Experience" questions that you need to answer and submit. Then you're ranked based on your answers among all other applicants for that level of position. They interview about the top ten (more if there are lots of positions open), and there could have been a hundred applicants. They refer to this list for the next year if any other positions become available at that level. Definitely have someone, or more than one someone, review and give feedback on your answers before submitting. It is beneficial to know and have someone who works full time at OPL help you with these questions (as they have already done their own sets of questions and scored highly). OPL managers also reportedly dislike the hiring process but tell applicants and employees that it is a city rule that the library has no power over.