As Rikko said, keep refreshing the page, appointments come up randomly. Keep in mind, you need to have a medical exam two weeks before the interview, and you should stay about 2-3 weeks after the interview as well. Stay on the Jerusalem side when picking a doctor.
You can set an appointment before they physically receive your files. It takes them about a month for the physical files to show up in Jerusalem, and they will email you when it does, but again, make the appointment before that confirmation.