Begin with a Criticall Evaluation, which measures your ability to multi-task, typing speed and ability to recall information.
After everyone does their Criticall, everyone is invited for an informational meeting, where they go over benefits, explain that you WILL work weekends, holidays, etc. (911 doesn't close) and try and weed people out who don't understand.
If you're still around, they look at your resume and how you scored on the Criticall and invite you back for an interview. Interview can be intimidating, is with Director, Supervisor and Manager. They will ask role-play questions, STAR questions.