Accessing Custom Fields in Zoho Booking in my Zoho Flow

Accessing Custom Fields in Zoho Booking in my Zoho Flow

Hi

In Zoho Bookings I have created some customer fields in my booking form and on is a field called "How do you want to me?".  The options are:

Telephone Call
Video Appointment
Visit our Office

I want access this field in Zoho Flow So I can send a different email to clients depending on which option they choose.

I have chosen the when a new appointment is created as the trigger - but I can't find any way to access this field in my decision box that I have added to the flow?

Any ideas?