If you just use your school Google calendar for setting appointments, this is the way to go. If you use more than one calendar, you might want to consider the you can book.me calendar setting service (also free).
If you want to use the appointment slots on Google Calendar, here is a quick how to
Sample email for the person asking for the booking/appointment:
Click on images to enlarge
This is great for parent-teacher conferences, tutoring schedules, and other meetings that need to be set individually. The basic service is free and connects to more than just your Google Calendar!
One of the programs I have found to use to book appointments is you can book.me. Using your Google account, you can create a personalized scheduling page where you can set up when you will take appointments. Anyone can see your schedule and book an appointment with you on any device. The appointment then goes straight into your calendar so you can set reminders, etc. What is even better is you don't have to go change your scheduling page; it is automatically updated with each appointment that is set.
Parent/Teacher conference
Asset/Equipment check-out
Student tutorial appointment
Sue Frantz (Highline Community College, Des Moines, Washington)
Counselor/Student conference
If you prefer to use video to learn, check this one out:
Sample email for the calendar/book me site owner:
Here are some uses for this in the schools:
Schedule tutorials with students
Administrators can schedule office hours for students or staff
Streamline observation scheduling
Schedule class time to meet with students on a project, paper, etc.
Schedule resources - gyms, auditorium, etc