The Calendar module is where your created appointments will be displayed.
Tour:
The calendar module can be accessed by clicking on the "Calendar" tab along the top of your screen after it's been enabled at Admin > Tabs Customization: 
Once there, you can click the "Toggle View" button in the top right to change the view to a horizontal view that doesn't have the appointment sidebar, and gives you options to only view appointments assigned to a specific User Account:
There is also an option to view the calendar with no sidebars, headers, or footers. This can be used on a larger public monitor that is set to full screen to display the calendar and the appointments to everyone in the office. You can access this view by adding "/calendar" to the end of your URL when you first click the calendar tab.
For example, your URL would look like this: https://XX.syncromsp.com/field_jobs/calendar (where XX is replaced with your subdomain)
How to create an appointment from the Calendar:
You can create an appointment straight from the calendar by filling out the "Schedule Appointment" sidebar on the right side of the calendar, shown here:
Select a ticket to schedule or re-schedule: Select an open ticket from the drop-down to assign this appointment to the chosen ticket
Subject: Fill in the Subject of the appointment. This will be displayed on the calendar itself and sent to your technicians if they have a Notification Set that emails them when an appointment is created (more on this later).
Description: Fill in the Description of the appointment. This is added to the description of the appointment which you can see by clicking on the appointment from the ticket.
Appointment type: Select the type of appointment this will be from this drop-down menu. This sets the type of appointment and drives which email is sent out to your customers, as well as auto-fills the Location field. You can read more about the different types of appointments and what they can be configured to do in our appointments article here.
Location: Fill in the location for the appointment and it will set the location for the appointment and populate the {{appointment_location}} tag in your appointment email templates.
Appointment Reminders Schedule: Select an Appointment Reminder Schedule if you would like reminders for the appointment to be sent out. You can set those up in our appointments article here.
All Day: Enable this setting if you would like the appointment to last all day, or multiple days long.
Start Time: Select the time that the appointment will start.
End Time: Select the time that the appointment will end.
Appointment Owner: Selecting an account here will choose an owner for this appointment.
Attendees: Select all of the technicians that will be attending this appointment, and it will add one appointment to each of their calendars.
Don't Email: Check this box to not send an appointment email to the customer on the ticket.
You can modify the appointment email that is sent out by navigating to: Admin > PDF/Email Templates > Email Templates. Once there you'll see the 'Ticket Appointment Email' and 'Non-Ticket Appointment Email', which you can modify to adjust the email that is sent when this box is unchecked.