Can I schedule one appointment for all the services in a work order?

Yes, you can schedule a single service appointment that covers all services in a Work Order — as long as no appointments already exist for the individual service line items.
To create a service appointment :

Go to:
Work Order Management > Service Appointments > Create Service Appointment
Select the work order for which you want to create the appointment.
The system will load all its details.
Enter the appointment timing:

Scheduled Start Date & Time
Scheduled End Date & Time
(Both should fall on the same day unless multi-day scheduling.)

Assign one or more Service Resources (Field Agents or Crews):

Resources appear only after start and end times are selected.
Only active field agents/crews in the selected territory and time slot will be listed.
Field agents who are part of a crew won’t appear individually during crew time.
Hover over an unavailable resource to see why they're unavailable.

If you’ve selected more than one individual resource (not a crew), you must choose a Lead

You can now choose to either Schedule or Schedule and Dispatch.

When to use Schedule

Click Schedule if you want to:

Save the appointment with all details entered
But notify the field agent later

This keeps the status as Scheduled (not yet dispatched)

When to use Schedule and Dispatch

Click Schedule and Dispatch if you want to:

Immediately notify the field agent via push notification
Automatically change the appointment status to Dispatched

After choosing Schedule or Schedule and Dispatch, confirm.

After creation:

You’ll land on the Service Appointment Details page.
From here, you can Dispatch(if you've only scheduled), Reschedule, Terminate, or Cancel the appointment as needed.

The appointment will also be visible:

Under the Appointments tab of the Work Order
In the Service and Parts tab (next to each related service line item)