The four exams are spaced out over four consecutive weekends. The exams take place on Sunday afternoons. In case of a weather-related cancellation, a Sunday exam will take place the following Saturday. About a month before an offering of the quals, a faculty member will post a message telling you how to sign up and what the sign-up deadline is. There is no official study group.
Students are free to form their own.
It is assumed that if you're ready to do doctoral-level work, you are also able to learn material without having a professor present it to you. You are responsible for all of the material in a qual syllabus, even if not all of it is covered in a particular course during a particular semester. Copies of past exams are available from the Computer Science Department secretary. You may take each part of the quals at most twice. That is, if you fail an exam the first time you take it, you may re-take it only one more time.