Use ticket automator to set due dates bases on create date

From what you describe, it’s probably best to do this via the “SLA and OLA Policies” section of the admin area.
You can set up the “respond within” times and choose what conditions apply:
 

You’ve also got options for different response times based on these conditions *and* priority but you can just set all the priority options to be the same if that’s an unnecessary division of tickets.

You don’t want to use SLA ? I think it would be easier with a custom SLA kriterier. 

With automation you need to use a Expression and have date/time as output and then action to set the due date. 

If SLA is not an option, you can use the Automator but need to calculate the date manually using a script.
But its a bit more annoying to set up, so we chose to use SLA’s

Steps to create an automation rule:

1. Go to Admin → Workflow Automator.
2. Create a new automation with these triggers:
   • Event: "Ticket is Created"
   • Condition: "If ticket field = X"
3. Action: Use a "Custom Action" (Requires a script).

require 'date' # Get the created_at date of the ticket created_date = DateTime.parse(event['created_at']) # Add 3 business days (excluding weekends) due_date = created_date 3.times do due_date += 1 due_date += 1 while [6, 7].include?(due_date.wday) # Skip Sat/Sun end # Update the ticket's due date { "due_by": due_date.strftime("%Y-%m-%dT%H:%M:%SZ") }