When booking an appointment, you have a choice to use a Template or not to use a template. A template will prefill all the information about the appointment such as duration, appointment, title, description and location. If you find yourself booking similar appointments frequently, it can be a good idea to use templates. If you are creating an appointment without a template, then you will have to create all the things a template would pre-fill. This can be good if you are booking just a one-off type of appointment.
Appointment Colors
Appointment colors are used to help you differentiate between different appointment types on the Calendar page as well as on your Google Calendar