How to tag a ticket as urgent based on the value of custom field

Sometimes you might want to allow your customers to mark the being submitted issue as urgent when submitting the issue through a contact form.
Let's see how to accomplish that scenario.
First of all you have to add a new field to a contact form of yours when creating/editing your form
After the  field is added set it to be of type of 'checkbox'
Once the form is equipped with the desired custom field you have to submit a test ticket through this form so that the custom field you added to the form gets added into the list of Ticket fields by the application. This step is essential!
Now it's time to create the Urgent Tag  and then the Rule that will automatically tag the tickets as "Urgent" if the customer submitted a ticket through that form and checked in the "Urgent" checkbox.
Now, if a customer submits a ticket via such form:
then it will be automatically marked as Urgent in LiveAgent
In the details of such a ticket you would see the value of  isUrgent checkbox (isUrgent is the system name of the checkbox that we defined earlier) is Y (the checkbox was checked)