Tickets of any form can be added to a schedule. Tickets can be scheduled on the timeline like phases with optional start date, end date and duration.
Access & permissions
How to access Schedule
Click Schedule
Create a Ticket
To create a new ticket directly in a schedule:
Open the more menu next to the parent phase.
Click + Create ticket
Add Existing Tickets
Open the more menu next to the parent phase.
Click + Add existing tickets 

Search for tickets and select the checkboxes of one or multiple tickets
Click Save 

After adding existing tickets to a schedule no duration is set. If you added the ticket to an automatically scheduled parent phase, it will always inherit a start date.
Edit scheduling details of a Ticket
To edit the parent phase, duration, scheduling mode, or start/end date:
Click on the ticket in the WBS (or open it from anywhere as described in View & Edit a Ticket)
Click Edit ticket schedule
Make your changes, e.g. enter a Duration
Click Save
Restructure Tickets in the WBS
Reschedule Tickets in the Gantt Chart
Remove a Ticket from a Schedule
Removing a ticket from a schedule will not delete the ticket: